can opiate addicts tell us about their relapse risk? subjective predictors of clinical prognosis

Addictive Behaviors, Vol. 18, pp. 473-490, 1993 Printed in the USA. All rights reserved.

0306-4603193 $6.00 + .OO Copyright 0 1993 Pergamon Press Ltd.

CAN OPIATE ADDICTS TELL US ABOUT THEIR RELAPSE RISK? SUBJECTIVE PREDICTORS OF CLINICAL PROGNOSIS

JANE POWELL,*.? SHARON DAWE,* DAVID RICHARDS,* MICHAEL GOSSOP,1- ISAAC MARKS,* JOHN STRANG,?

and JEFFREY GRAY* *Departments of Psychology and Psychiatry. Institute of Psychiatry. London

tDrug Unit, National Addiction Centre, Maudsley Hospital/Institute of Psychiatry. London

Abstract - Given the high relapse rate of opiate addicts following detoxification, it is pertinent to identify whether any subjective variables mediate outcome, since these may then be targets of treatment. The present study assessed personality, cue-elicited craving, outcome expectancies for drug use, and self-efficacy for resisting drug use, in 43 opiate addicts receiving inpatient detoxification in either a specialist drug-dependence unit or a behavioral/ general psychiatric ward. within the context of a randomised, controlled-treatment trial. Subjects were followed-up at between I and 3 months and again at 6 months after discharge. Frequency of drug use was not predicted by any of the subjective variables at the first follow-up: but at 6 months, subjects with lowler self-efficacy and higher positive outcome expectancies were found to be using less often. Latency to first lapse was greater in subjects with higher anxiety and neuroticism scores. Precipitants to the first lapse were identified. but none of the predicted relationships between subjective variables and circumstances of lapse emerged. It is suggested that greater awareness of personal vulnerability may promote effective coping strategies.

A recent study following the progress of opiate addicts who completed detoxification in an inpatient treatment facility (Gossop, Griffiths, Bradley, & Strang, 1989) found there to be greater diversity in outcome than had formerly been supposed. In particular, whilst the majority of subjects did lapse to opiate use on at least one occasion, at 6 months after discharge, fewer than one third were using daily, and just over half (51%) were completely abstinent. These data flew in the face of the genera1 pessi- mism of clinicians, fuelled by earlier reports of 80% relapse rates (see, e.g., review by Lipton & Maranda, 1983), and by the disproportionate clinical contact between the service and “treatment failures.” The data open up the interesting prospect that it may be possible, at an early stage in admission, to identify individuals whose prognosis is particularly poor, and to target these cases for intensive interventions designed specifically around their personal risk factors.

Some demographic factors are already reasonably well established as predictors of poorer outcome (e.g., sex, socioeconomic status, etc.), but provide little opportunity for direct clinical modification. However, the use of drugs is an active hehauiour, selected at some level by the individual, and not an event with some simple physical determinant. No demographic factors are invariably associated with addiction, and their predictive status must therefore be mediated through more proximal precur- sors, such as material and psychological resources determining exposure and re-

We are grateful to the Medical Research Council (MRC) for funding this programme of research. Acknowledgements are also due to the staff of the Drug Dependence Unit and Tyson Webt II at the Bethlem hospital for their help and cooperation, to Helen Annis for agreeing to our use of an adapted version of her Situational Confidence Questionnaire, and to Alan Pickering for statistical advice and comments on the manuscript.

Requests for reprints should be sent to Jane Powell. PhD, Institute of Psychiatry. De Crespigny Park. Demark Hill, London SE5 8AF, United Kingdom.

473

474 J. POWELL et al

sponses to opportunities for drug use. For instance. one might conjecture that the lower abstinence rates recorded by Gossop, Green, Phillips, and Bradley (1987) amongst women might reflect not an effect of sex per se, but (hypothetically), less self-confidence in the ability to cope with stressful situations without using drugs. If this interpretation is valid, then the most directly relevant clinical task is to develop appropriate methods for identifying and assessing these intervening variables, and thence to target them for therapeutic change. The detailed study of psychological variables associated with abstinence from alcohol has indeed pinpointed a number of subjective predictors. Two of the most pertinent constructs are orrtc~~mc c.vpprcrrrn-

tics (Marlatt & Gordon, 1985) and sc)(f+fJctrcy (Bandura, 1977). An outcome expectancy is the belief that an event (here, drug ingestion) will result

in a specific consequence. either positive or negative. Brown (1985) assessed a range of outcome expectancies for alcohol use in alcoholics admitted to a short residential- treatment programme, and found that a total positive expectancy score significantly predicted not only whether or not subjects relapsed during the following 12 months, but also the frequency of problem drinking within the year. The higher the positive expectancy score, the poorer the outcome. A number of other studies have found relationships between alcohol expectancies assessed at one point in time and actual drinking behaviour up to 1 year later (e.g.. Christiansen,.Smith. Roehling, & Gold- man, 1989; Stacy, Widaman. & Marlatt, 1990). Most recently, a detailed analysis of data collected prospectively over a 9-year period, commencing in subjects’ adoles- cence. by Stacy, Newcomb, and Bentler (1991) revealed not only that adolescent expectancies for alcohol and marijuana use predicted actual use in adult life. but also that this relationship was at least partially independent of drug experience already gained prior to the initial assessment. Thus, expectancies appeared to play a causal role, rather than simply being epiphenomena of an existing behavioural tendency.

The second construct. self-efficacy, refers to the belief that one has the ability to behave in a certain way. in certain well-defined situations: in the present context, the behaviour in question is usually designated as “resisting the urge to use drugs.” The

utility of this construct in predicting clinical outcome has been explored in various studies with alcoholics and with smokers. In an early study, Rist and Watzl (1983) found that, amongst a group of I45 female alcoholics, those who relapsed to drinking within 3 months after discharge from inpatient treatment had rated themselves prior to treatment as being less able to resist social pressure to drink than had abstainers. Annis and Davis (1986) assessed self-efficacy for resisting the temptation to drink in a range of common high-risk situations in a group of alcoholics participating in an outpatient treatment programme. Detailed accounts of any drinking episodes during treatment were taken, and a preliminary analysis suggested that their initial lapses to heavy drinking were particularly likely to occur in situations for which they had given low self-efficacy ratings. This was not. however, the case for episodes of light drinking. More recently, Solomon and Annis (1990) followed-up a hundred alcoholics after discharge from residential treatment, having assessed self-efficacy during their admission. Although self-efficacy ratings were not predictive of outcome in the full sample, when the subgroup who had resumed drinking at follow-up were considered separately, an inverse relationship emerged between self-efficacy and average daily consumption (i.e., among “lapsers.” those who had rated their self-efficacy lower were drinking more heavily). With smokers, significant correlations have likewise been found between ratings of self-efficacy for resisting smoking and subsequent smoking behaviour (Baer, Holt. & Lichtenstein. 1986: Sperry & Nicki, 1991):

Subjective predictors of opiate relapse 475

it should be noted, however, that in these studies self-efficacy ratings were closely related to concurrent smoking behaviour, and the causal status of self-efficacy in promoting subsequent behaviour is thus equivocal.

In addition to these cognitive variables, it seems likely that personality traits also might modulate the individual’s response to potential risk situations, since there is an extensive literature documenting the relationships between certain measurable di- mensions of personality and observable response tendencies. For example. individuals scoring highly on the Extraversion scale of the Eysenck Personality Question- naire (EPQ) (Eysenck & Eysenck, 1975) are demonstrably more gregarious than low scorers, whilst those low on Extraversion and high on the Neuroticism scale are typically more sensitive to external stressors and are particularly prone to develop anxiety-related disorders (Eysenck & Rachman, 1965). Consider the potential impact of differing personality profiles on reactions to situations which have been found to be frequently associated with relapse to addiction. Cummings, Gordon, and Marlatt (1980) coded addicts’ descriptions of events precipitating their first relapse after detoxification into eight mutually exclusive categories, and reported that interpersonal conflict, negative emotional states, and social pressure together accounted for 71% of the relapse precipitants. The preponderance of relapses attributed by addicts to the experience of negative emotional states, in particular, has been con- firmed in several subsequent studies using alternative data collection and coding systems (e.g., Bradley, Phillips, Green, & Gossop, 1989; Heather & Stallard, 1989). Given the robustness of this finding, we might predict that anxiety- or depression- prone individuals would be especially likely to experience heightened dysphoria at an early stage after detoxification, and hence would be at particularly high risk of relapse. Likewise, highly impulsive patients might be expected to be more at risk in situations where drugs are suddenly made available (e.g., in social situations). How- ever, although some attempts have been made to identify personality characteristics which predispose to the initial onset of addiction (see, e.g., Kandel. 1978), a literature search revealed no studies of the relationship between addicts’ personality and their clinical prognosis following detoxification.

The final subjective variable to be considered here is “craving.” Numerous au- thors have argued for an inBuential role of classically conditioned responses in triggering detoxified addicts to renewed drug use. Briefly, it is postulated that exposure to internal or environmental stimuli formerly associated with drug use may trigger a conditioned increase in the drive to seek out and use drugs, a drive state which may be experienced subjectively as craving (see Powell et al., 1990, for a more detailed discussion). It has repeatedly been demonstrated, in support of this, that exposing addicts to drug-related cues in a laboratory setting is associated with eleva- tions in self-reported craving and with reactions in various other response systems (e.g., Stockwell, Hodgson, Rankin, & Taylor, 1982; Teasdale, 1973; Ternes, O’Brien, Grabowski, Wellerstein, & Jordan-Hayes, 1980). On this basis, cue exposure has been advocated as a treatment method which, by extinguishing these responses, should shield the addict from one class of relapse risk and hence promote

abstinence rates (e.g., O’Brien Ehrman, & Ternes, 1986; Wikler, 1965). However. there is, as yet, no direct evidence of any association between responses elicited in the laboratory and subsequent prognosis.

Given the potential clinical importance of defining and assessing subjective predictors of outcome in addicts, and the relative dearth of investigation of these factors in opiate addiction, the present paper describes data which were gathered as part of a

476 J. POWELL et al.

clinical treatment trial of cue exposure with opiate addicts. The experimental design

and results of the treatment evaluation will be presented elsewhere (Dawe et al., in press); however. there was no pronounced effect of cue exposure on outcome. and

so the data concerning predictors of follow-up have been reported here without reference to whether or not subjects in fact received this treatment.

M E 1‘ H 0 D

For reasons concerning the detailed evaluation of the cue exposure intervention

(Dawe et al., in press). opiate addicts requesting detoxification and who were eligible

for the study were initially randomly allocated between two treatment sites within the Bethlem/Maudsley Hospital: either the Z&bedded specialist Drug Dependence

Unit (DDU), which offers a IO-day methadone detoxification (Gossop et al.. 1989) followed by a rehabilitation programme involving group and individual work, initially contracted to last 8 weeks in total; or a ward specialised for the treatment of beha-

vioural disorders as well as general psychiatric problems (Behavioural and General Ward [BGW]), with up to two addicts admitted at any one time. offering a short

clonidine detoxification programme (Kasvikis et al., 1989). followed by either 2- to 3- week inpatient cue-exposure treatment, or immediate discharge.

Since the brief clonidinc detoxification given on the BGW was medically unsuit-

able for some addicts (e.g., due to hypertension. pregnancy. HIV-related illness.

concurrent dependence on other drugs entailing an additional and mot-e prolonged detoxification), subjects excluded from the initial allocation for these reasons were subsequently allocated to cue-exposure or non-cue-exposure conditions within the

DDU. Subjects were excluded from the study entirely if they had a concurrent psychiatric diagnosis other than addiction: if they were not physically dependent on

opiates; if they were participating in another ongoing drug (naltrexone) trial: or if their planned hospital admission was constrained in length or in treatment approach

by other considerations (e.g., short detoxification only). All subjects participated in the treatment trial voluntarily. and they were allowed

to drop out at any stage. However, if they completed the requisite treatment period. strenuous efforts were made to contact them at approximately I and 6 months

following discharge from the hospital. In the case of subjects treated in the DDU, treatment completion entailed a minimum admission length of 5 weeks plus partici-

pation in a posttreatment assessment. For BGW subjects, completion of the control condition was defined by a minimum of 4 days opiate-free. initially on clonidine,

which was discontinued when symptoms had substantially disappeared. For BGW cue-exposure subjects. study completion consisted in receiving at least six treatment sessions and a final assessment spread over a minimum of 3.5 weeks after detoxilica- tion. For all subjects, an initial assessment comprising a semistructured interview and the completion of a range of questionnaires and checklists was conducted soon

after admission. At follow-up, subjects were interviewed concerning details of any drug use which

had occurred in the preceding month, and (when relevant). were also asked to describe the circumstances of their first lapse to opiate use. This permitted explora- tion of specific associations between individual predictor variables and particular lapse situations. For those subjects who were not in residential rehabilitation at


follow-up, urine samples were requested and analysed for the presence of the major psychoactive drugs, in order to verify self-reported drug use.

Assessment measures At the initial assessment interview, detailed information was collected concerning

demographic characteristics, history of drug use, current drug use, and previous attempts at detoxification and abstinence. In addition to giving this basic information, subjects completed a number of questionnaires and checklists, of which some were well-established standardised instruments and others were specially designed for the purposes of the study. Specifically, these included:

1. The EPQ (Eysenck & Eysenck, 1975), from which scores on the Neuroticism dimension (EPQ-N) were computed.

2. The Trait Anxiety scale of the State-Twit Anxiety Inventory (Spielberger, Gor- such, & Lushene, 1970), on which high scores have been interpreted as directly indexing the low-Extraversionihigh-Neuroticism quadrant of Eysenck’s (1967) model of personality and hence to be particularly characteristic of patients susceptible to clinical anxiety disorders.

3. The tmpulsivity-7 questionnaire (I-7; Eysenck et al., 1985), which was used to measure the personality dimension of Impulsivity.

4. The Motivational Checklist (Powell, 1990): this instrument has been described in an earlier paper (Powell, Bradley, & Gray, 1992), and is designed to assess outcome expectancies for opiate use. It comprises two scales; one listing 14 common positive consequences (“PROS” of opiate use); and the other, 17 common negative consequences (“CONS” of opiate use). Addicts rate the degree to which each consequence has been important either in their most recent use of opiates or in their decision to quit; in all cases a O-4 rating scale is employed. with 0 indicating “no importance” and 4, “extreme importance.” PROS and CONS scale scores are computed by simply adding together scores on each item within the scale; a third index, Motivational Balance, represents the difference between the scale scores (PROS - CONS) and is intended to index the extent of imbalance between positive and negative outcome expectancies.

5. The Conjidence Questionnaire (CQ) is an IX-item checklist designed to assess self-efficacy for the ability to remain drug-free in a range of specific high-risk situations, and was based closely on the Situational Confidence Questionnaire developed by Annis (1982) for use with alcoholics. Subjects rated each situation on a IO-point scale, with 1 representing no confidence, and IO, complete confidence in their ability to resist any urge to use in that situation. A total score was derived by simply adding together the confidence ratings for all situations.

This questionnaire was readministered at a predischarge assessment after the cue-exposure treatment/control procedures were complete, except in the case of BGW control subjects, who were discharged immediately after detoxification.

6. A Cruving Test (CT) was administered to all subjects after they had completed detoxification and was repeated at the end of the experimental period for all subjects except those in the BGW control group. The two assessments will be referred to as CT1 and CT2, respectively. Details are given elsewhere (Dawe et al., in press). In brief, the tests entailed exposing subjects, first of all, to a neutral stimulus (a picture unrelated to drug use), and then to a drug-related stimulus (a

47x J. POWELL et al

picture of someone using opiates via the subject’s own preferred route). During these S-minute presentations. the subject gave ratings of craving at l-minute intervals, using a Y-point scale. on which 0 represented no desire at all for opiates and 8 represented the most intense craving imaginable. Ratings of physical symptoms and mood state were taken before and after each stimulus presentation.

Mean levels of craving were computed separately for the neutral and drug stimuli, with (Drug - Neutral) scores providing an index of “cue-specific”

craving.

At both follow-up interviews, subjects were asked in detail about their drug use in the month preceding the interview. completing the Drug and Alcohol scale from the Addiction Severity Index (ASI; McLellan. Luborsky, O’Brien, & Woody. 1980). This requires them to indicate, for a wide range of classes of drug, the number of days, in the 30 preceding the interview, on which each drug has been taken. Where possible, a urine sample was also taken.

Those subjects reporting any instance of opiate use were then asked to describe what they felt had led up to their first lapse. Their narrative accounts were initially coded by two independent raters for the presence or absence of a number of specific risk factors. There was agreement on 87% of the codings, and in the few instances of disagreement, a consensus was arrived at through discussion. The classification of risk factors included the following items: negative mood state: positive mood state: physical discomfort; direct social pressure to use (drugs made explicitly available): indirect social pressure (presence of other known drug users in absence of immediate drug availability); interpersonal conflict and/or social anxiety; use of other substances such as alcohol. marijuana. etc.: and presence in an area associated with drug use. This classification was loosely based on the system described by Cum- mings et al. (1980). but following the arguments advanced by Bradley et al. ( 19X9), categories were not mutually exclusive. Each risk was endorsed only if it was clear that it had occurred p~‘io,- to the sub.ject‘s decision to use drugs. Although this procedure does not require subjects to consider. systematically. the relevance of a

specified range of factors (as required when a checklist is administered; see Heather, Stallard. & Tebbutt, 1991). it was felt that it would result in reporting of the most subjectively salient factors.

S U B J E C T S

Of I83 subjects who presented requesting inpatient treatment for their addiction, and who were eligible for the study, 69 were finally admitted, the others failing to t-e- present or to take up their places. Of the 69 who were admitted for inclusion in the trial, 43 subjects completed the inpatient components of the study. and so were eligible for follow-up. Forty-eight were admitted to the DDU, of whom I9 dropped out and 29 completed, compared with 21 admissions to the BGW. of whom I4 completed and 7 dropped out early. This marked attrition rate, particularly between initial contact with the service and actual admission. is of interest in its own right and is the subject of a separate paper currently in preparation.

For those who completed the study, the mean duration of admission was 12.3 weeks (SII = 2.X) for the DDU subjects and 1.9 weeks (SL> = I .5) for those in the BGW. There were 36 men and 7 women, and their mean age was 29.7 (SL) = 6.7) years. Their mean number of years of opiate addiction was I I. I (SD = 6.3). Eighty-


eight percent stated their preferred opiate to be heroin, though 47% were, in fact, using methadone, primarily, and 70% preferred to use intravenously, compared with 23% preferring to “chase the dragon” (i.e., inhale).

Fifty-six percent of the subjects used at least one other drug in addition to opiates on a regular basis (i.e., more than 3 days in 4), as follows: cannabis (21%), sedatives (19%), alcohol (12%), and cocaine (7%). No subjects were regular users of barbitu- rates, amphetamines, inhalants, or hallucinogens.

Thirty-nine (91%) subjects were successfully contacted at the first follow-up - on

average, 7.3 weeks after discharge (SD = 4.5 weeks); 37 (86%) were traced at the second follow-up - on average, 31.5 weeks after discharge (SD = 6.2 weeks).

These high follow-up rates compare favourably with those achieved in other outcome studies (e.g., Brown, 1985; Solomon & Annis, 1990).

Data analysis In analysing relationships between predictor variables and outcome, the data were

examined not only for the full sample of subjects (ALL), but also for various sub-

groups. One consideration was potential differences between subjects treated in the DDU

and subjects treated in the BGW. In particular, all DDU subjects were necessarily inpatients for at least 5 weeks, in order to reach the second Craving Test and become study completers, and, in fact, the shortest length of stay was 8.3 weeks. By contrast, the BGW subjects receiving cue-exposure treatment were admitted for an average of 3.7 weeks, whilst the BGW control subjects were admitted, on average, for only 6 days. Consequently, the BGW groups (particularly the controls) may not have needed to be intrinsically as motivated in order to succeed in meeting study requirements. Secondly, whilst residential rehabilitation was presented persuasively as a discharge plan for DDU patients, BGW subjects were simply informed about these options. In practice, 45’% of DDU subjects were discharged to rehabilitation, compared with only 14% of BGW subjects. Analyses were therefore repeated forjust the DDU subjects (DDU-ONLY), in order to examine a group more homogeneous with respect to motivational factors, treatment experience, and discharge planning.

Secondly, it was felt that subjects who were in residential treatment at follow-up would have been insulated from many of the normal risks encountered by subjects returning to the community, such that a range of vulnerability factors might be of relatively little influence. Analyses were therefore performed at each of the two follow-up points for only those subjects who were living in the community at that time: the COMMl and COMM2 subgroups, respectively.

When the distributions of days of opiate use at the first and second follow-ups were examined, a bimodal distribution was apparent at 6 months, with all but four subjects either being completely abstinent or using on a daily basis. Outcomes at 6 months were therefore categorised as either “no/infrequent use” (less than IO days in the month) or “regular/daily use” (between I I and 30 days). Point-biserial correlations were used to examine the relationships between 6-month outcome and the various predictor variables.

Since, as detailed in the introduction, specific predictions were made concerning the direction of associations between subjective variables and outcome, one-tailed significance levels for the observed correlations were computed. However, where preliminary inspection revealed sizeable correlations in the oppositr direction to that predicted, two-tailed tests were used to explore the significance of the findings.

480 J. POWELL et al

A second outcome variable, “days until first lapse,” was also analysed. Since not all subjects had. in fact, reported a lapse by the time the follow-up period was complete, survival analysis (Cox & Oakes, 1984) was used to examine these data, which were censored at day I80 (6 months after discharge from hospital). Again, analyses were conducted for DDU-ONLY and COMMl subgroups, as well as for ALL subjects; COMM2 data were not analysed separately. since only two subjects entered rehabilitation after the first follow-up and both had lapsed prior to this.

Data have been presented in detail for ALL subjects, but where results within the subgroups differed markedly (e.g., in terms of whether or not they reached significance). these are also specified.

At the first follow-up, there was 80%) agreement between self-report and results of urinalysis, and at the second follow-up, there was 83f% agreement. Where there was a disagreement. this was often because the subject reported occasional use, but this was not picked up in the urine sample.

The data concerning days until first lapse are illustrated in Figure 1. where the survival curve follows approximately a Weibull distribution (see, e.g., Kalbfleisch & Prentice. 1980).

Figure 2 shows, for those subjects who were traced at the two follow-up points, the percentages who reported having been opiate-free for the last 30 days, having used opiates occasionally (fewer than 3 days per week on average). and having used opiates regularly (3 days or more per week on average).

At the first follow-up, I7 subjects had been entirely opiate-free for the preceding 30 days: I I were using occasionally; and I I were using regularly. Within the same month, regular use of other drugs was reported only for sedatives (4 subjects) and

60

0 I I I I I 1 I I 1 1 I I 1 I I 1

0 . 6 . 12 . 18 . 24 . 30 . 36 . 42 . 48 . 54 , 60 . . . . . .I80

DAYS AFTER DISCHARGE

Fig. I. Survival curve: Days until first lapse.


‘OO& 80 -

60 -

40 -

20 -

O-

Fy;or-,U,p, 1 F;;01”-3u,~ 2

FREQUENCY OF OPIATE USE

Fig. 2. Opiate-using status at each follow-up (percentages of subjects contacted).

cannabis (1 subject). Occasional use of alcohol was reported by 22 subjects, sedatives by 6, cannabis by 10, cocaine by 6, and amphetamines and hallucinogens each by 1. There was little evidence of substitution: of those subjects still abstinent from opiates or using them only occasionally, regular use of other drugs was rare (alcohol, 1 subject; sedatives, I subject; and cannabis, 2 subjects).

At the second (6-month) follow-up, 22 subjects had been entirely opiate-free for the preceding 30 days: 3 were using occasionally, and 12 had returned to regular or daily use. Regular use of other drugs was relatively rare, with regular alcohol use reported by 4 subjects, sedative use by 2, cocaine by only I, and cannabis by only 1. Occasional use was more common, with 14 subjects using alcohol, 4 using sedatives, 4 using cocaine, and 10 using cannabis. Again, there was little evidence of substitution: of those subjects still abstaining from opiates or using them only occasionally, regular use of alcohol was reported by only one subject, and no other drugs were used regularly by any subject.

Craving and outcome Correlations were computed between craving levels reported in the two Craving

Tests (CT1 and CT2) and days of opiate use at the two follow-ups. For ALL subjects, sample sizes for these correlations varied between 28 and 39, this variation arising partly because subjects in the BGW control group did not receive CT2, and also because incomplete data were available at the two follow-up points.

Neither absolute levels of craving to the drug-related stimulus, nor cue-specific increases in craving (i.e., Drug - Neutral), either in CT1 or in CT2. were predictive of opiate use at either the first or second follow-ups, with correlations ranging between 0.02 and 0.24 (all ns). There were, likewise, no significant relationships within any of the DDU-ONLY, COMMI, or COMM2 sub-groups.

No relationship was found between any of these four craving variables and days to first lapse, either for ALL subjects, or in any of the sub-groups (x’ ns in each case).

482 J. POWELL, et al

Correlations were computed between the three personality variables (EPQ-N, Trait Anxiety, and Impulsivity) and days of opiate use at the two follow-ups, and were based on data from between 31 and 37 subjects. None of the correlations were significant. ranging between -0.27 and 0.04. This was true also when the data were analysed for the DDU-ONLY, COMM I, and COMMZ subgroups.

When survival analysis was used to examine the relationships between personality and days until first lapse, none of the variables emerged as significant predictors either for ALL or for DDU-ONLY subjects. By contrast, for COMMI subjects, EPQ-N was predictive. with x? = 5.61, p < 0.02, as was Trait Anxiety (x2 = 7.3. p < 0.01); and the relationship with lmpulsivity approached significance (x? = 3.6, p = 0.06). All these relationships were positive in sign: thus, higher levels of neuroticism, trait anxiety, or impulsivity were associated with a longrr time until first lapse.

Correlations between scores on the Motivational Checklist and days of opiate use at follow-up were based on data from 37 subjects at the first follow-up and on data from 35 subjects at the second follow-up.

At the first follow-up, neither the total scale scores (PROS and CONS) nor motivational balance (PROS - CONS) predicted opiate use for ALL subjects, all corrcla- tions being less than 0.10. There were, likewise. no significant correlations within either the DDU-ONLY or COMMI subgroups. At the second follow-up. however, whilst the total CONS score again failed to predict opiate use, there was a negative correlation between total PROS score and days of opiate use: the higher an individual’s outcome expectancies, the fewer days he/she was actually using opiates. This was opposite in direction to the predicted relationship. and a two-tailed test showed the correlation to be significant (1. = -0.40, II = 3S, /7 < 0.02). Within the DDU-

ONLY subgroup, the same pattern was observed. the single predictive relationship being between PROS and days of opiate use at 6 months (r = -0.50, 17 = 24, p < 0.02). None of these relationships was significant within the COMM2 subgroup.

PROS were significantly associated with days until first lapse for ALL subjects (x? = 6.7, p < 0.01). for DDU-ONLY subjects (x2 = 4.8.11 < 0.05), and for COMMI subjects (x2 = 7.5, p < 0.01). In all cases, the higher the PROS score, the longer the time until first lapse. There was a trend towards a significant relationship between CONS and days until first lapse in the DDU-ONLY subgroup (x’ = 3.6, p = 0.06). with higher CONS scores associated with greater time until first lapse, but not for ALL subjects, nor within the COMMI subgroup. Motivational Balance was unre-

lated to days until first lapse in every case.

Scores on the Confidence Questionnaire from the pre- and posttreatment assessments have been designated CQI and CQ2. respectively, and it should be noted again that subjects in the BGW control group did not receive CQ2 because they were discharged as soon as detoxification was complete. For ALL subjects, correlations with days of opiate use at the two follow-up points are based on sample sizes of between 24 and 35.

At the first follow-up, neither of the CQ scores predicted frequency of opiate use (Y < 0.25, in each case), and this was true also for subjects in the DDU-ONLY and COMMI subgroups. At 6 months, however, there were a number of positive correla-


tions between CQ indices and days of opiate use, suggesting that, contrary to prediction, those individuals reporting greater confidence in their ability to resist drug use were in fact using more heavily. Two-tailed significance tests were therefore used. The association between CQI and days of opiate use approached significance (r =

0.32, n = 33, p < 0.07) for ALL subjects, and achieved significance for the DDU- ONLY subgroup (r = 0.45, n = 23, p < 0.05), though not within the COMMZ group. CQ2 was significantly correlated with days of opiate use for ALL subjects (r = 0.5 I, n = 24, p < 0.02), as well as within the DDU-ONLY subgroup (r = 0.5 I, II = 23, p < 0.02) and within the COMM2 subgroup (r = 0.58, n = 16, p < 0.02).

Survival analysis of relationships between CQ scores and days until first lapse, however, showed no significant association either for ALL subjects or for the sub-

groups.

Relationship between predictors of opiate USC at 6 months

The two subjective variables which significantly predicted days of opiate use at the second follow-up for ALL subjects, namely PROS and CQ2 scores, were found to be highly correlated with each other. Thus, within the full sample of subjects who received the two questionnaires, the correlation was -0.56 (n = 28, p < 0.005). A stepwise multiple regression analysis was conducted to ascertain whether or not they accounted for separate proportions of the variance in days of opiate use, and revealed almost complete overlap, with CQ2 alone yielding a multiple R of 0.44 (p = 0.05), and PROS failing to make any significant additional contribution. The corre-

‘lation between PROS and days of opiate use, with CQ2 partialled out, fell to -0.02 (ns).

Factors predicting M>hich subjects elected for residential r~~habilitation

T-tests were used to compare those subjects who were voluntarily in residential rehabilitation at the first follow-up with those who returned to the community. The analyses were performed both for ALL subjects and for DDU-ONLY subjects.

Sample sizes ranged from 25 to 39 for ALL subjects, and from 22 to 25 for the DDU-ONLY subgroup. Neither any of the craving scores nor any of the three personality variables differentiated those going to residential rehabilitation from those who did not, whether ALL subjects, or just the DDU-ONLY group were considered (t < 1.5 in each case). Likewise, the total CONS score on the Motiva- tional Checklist failed to predict which subjects elected for residential rehabilitation, as did Motivational Balance (t < 1.7, in each case).

However, the total PROS score on the Motivational Checklist did differ significantly between rehabilitation and nonrehabilitation subjects, for ALL subjects (t = 3.1, &= 35, p < 0.005) and for DDU-ONLY subjects (t = 2.3, d/‘= 23, p < 0.05), with higher scores (i.e., higher ratings of positive outcome expectancies) among those who went on to further residential rehabilitation.

Scores on the CQ, indexing self-efficacy, did not differ between those who went to further rehabilitation and those who did not when the comparison was made for ALL subjects (t < - 1.7 for all CQ indices): but for DDU-ONLY subjects, there was a trend for CQI scores to be lower among those subjects who did go on to residential rehabilitation (t = -2.01, d’= 22, p < 0.07). Thus, for this subgroup, the lower an individual’s rated self-efficacy, the more likely he/she was to go on to rehabilitation. No such relationship was found with CQ2 in this subgroup.

484 J. POWELL et al

Table I. Relapse precipitant<. in descending order of frequency cited

Kelap5e precipitant Number of

wbjects

Negative emotional state5 I9 Indirect wcial pressure II Direct social pra\ure 6 lnterperaonal stress 4 Area\ associated with drugs 4 Physical discomfort 2 Use of other substances I Pwitive mood 0

Of the 28 subjects who reported at least one lapse to opiate use, the numbers citing each of the coded precipitants are shown in Table 1, in descending order of inci- dence. Where a precipitant was cited by at least four subjects. hypotheses concerning relationships with personality variables were explored. using t-tests to compare subjects citing the precipitant with those who did not.

It was predicted that subjects citing “negative emotional states” would score more highly on EPQ-N and Trait Anxiety than the other subjects. Neither of these predictions was supported. Likewise, it was predicted that these same subjective variables would be positively associated with the precipitant of “interpersonal stress:” but, again, no such associations were found.

Both “direct social pressure” and “indirect social pressure” were hypothesised to be particularly salient for subjects scoring highly on Impulsivity, but this was not borne out. Highly impulsive subjects were also hypothesised to be more vulnerable to being in an “area associated with drug use:” but again. no association was found.

I> I S C U S S I 0 N

Fifty-nine percent of the addicts participating in this study who were followed-up 6 months after discharge from hospital were completely abstinent from opiates at that time. a rate which is slightly higher than the 51% reported by Gossop et al. (1989). However. since Gossop et al. (1989) found a positive association between prognosis and length of hospital admission, this difference may well simply reflect the different inclusion criteria in the two studies: whilst Gossop et al. (1989) followed-up all patients completing inpatient detoxification in the DDU, the present investigation required the majority of subjects (those in the DDU). to have completed an admission of at least 5 weeks. In both studies, outcomes at the earlier follow-up (l-3 months in the present case) were much less clear-cut than at 6 months. with a markedly higher proportion of subjects using on an occasional basis at the earlier point. At neither follow-up point here was there convincing evidence of drug substitution: only four opiate-free subjects were using other substances regularly at first follow-up, and only one at 6 months.

It was striking that at the earlier follow-up, when 91% of the subjects were traced and interviewed, not one of the subjective variables assessed during admission was predictive of frequency of opiate use in the month preceding the interview. This was


true whether the sample was considered as a whole, including both those patients admitted to the DDU and those admitted to the very different regime and milieu of the BGW, or whether the more homogeneous DDU-ONLY subsample was examined separately. Likewise, when addicts who elected for discharge to further residential rehabilitation were excluded, on the grounds that these individuals were protected from many of the risk situations arising in the “real world,” again, it

proved impossible to predict frequency of opiate use. These findings differ from those of a previous study in which the number of

protective factors identified by opiate addicts, and a rating of their confidence that they would remain drug-free, were both found to be predictive of frequency of drug use during the first 2 months after leaving treatment (Gossop, Green, Phillips, & Bradley, 1990). It is worth noting that the confidence measure used in that study was a global judgment of the likelihood of remaining drug-free and thus differed from the CQ used in the present study, which inquired about self-efficacy in a number of specific risk situations. It may be, therefore, that within their single confidence ratings, subjects in Gossop et al.‘s (1990) study took into account a wide range of relevant issues including self-efficacy, protective factors, motivation, etc. It would be interesting in the future to investigate the relationship between confidence, self- efficacy, and other more specific subjective indices.

None of the indices of craving assessed in pre- and post-treatment laboratory cue- exposure tests showed any predictive utility at either follow-up point. Given the extensive literature documenting the occurrence of conditioned responses within both experimental settings and (anecdotally) in the addicts’ real-life environment, this must cast some doubt on the widely held view (e.g., Childress, McLellan, & O’Brien, 1986; Wikler, 1965) that conditioned craving, occurring after detoxification, increases the risk of relapse. It may be, of course, that craving reported in the controlled laboratory setting is not systematically related to craving occurring natu- ralistically, or, alternatively, that subjective craving is not an accurate index of conditioned responses elicited at a physiological level. Whilst the present data do not necessarily discredit the clinical validity and relevance of conditioned responses to relapse, nor the application of extinction procedures via systematic cue exposure, they do suggest strongly that subjective craving reported by addicts should not be treated automatically as a sign of increased vuhierability.

However, other subjective variables did emerge as predictors of opiate use at the 6-month follow-up. In particular, positive outcome expectancies, indexed by the total score on the PROS scale of the Motivational Checklist, were negatively correlated with the number of days on which opiates had been used in the preceding month, both within the full sample (u = -0.39, p < 0.05). and, more markedly, within the DDU-ONLY subgroup (u = -0.50, p < 0.01). Assuming that perception of recent drug effects, as rated on the Motivational Checklist. is indeed a good indicator of current outcome expectancies, this indicates that those addicts who perceived opiate use to be most rewarding actually had hefter outcomes. This relationship is opposite in direction to that reported in prospective studies of substance use by both nonad- diets (e.g., Christiansen et al., 1989; Stacy et al., 1991) and alcoholics (e.g., Brown, 1985), and also contradicts the theoretical prediction that strong positive outcome expectancies should increase vulnerability to relapse. It is conceivable that the observed correlations arose by chance, since 13 predictor variables were examined at each of the two follow-up points. However, the correlation between PROS and days of opiate use at the second follow-up for the DDU-ONLY subgroup in particular was

486 J. POWELL et al.

significant at the 0.01 level, using the more conservative two-tailed test, and an alternative interpretation therefore merits consideration.

It is relevant, first of all, to consider the finding that when subjects were categorised on the basis of whether or not they opted for further residential rehabilitation, those who did so had significantly higher PROS scores than those who did not. One interpretation is therefore that addicts reporting more pronounced positive outcome expectancies for opiate use felt themselves to be at particular risk, and protected themselves by going on to further rehabilitation, away from the risks present in the community. The reality of this increased risk was not, however. borne out for subjects who had returned to the community by the 6-month follow-up: although the correlation of 0.30 between days of opiate use and PROS fell short of significance. it still suggested a tendency for those with mot-c positive outcome expectancies to do better. It is possible that subjects who give higher PROS ratings are more analytical and realistic about their vulnerability to temptation and are better equipped to develop constructive coping strategies, whether in terms of gaining a planned admission to further rehabilitation or in terms of active coping within the community. Consistent with this argument, there was evidence that subjects with higher PROS scores had their first lapse to opiate use. on average. later than those with lower scores. Survival analysis found this relationship to be significant, not only within the full sample, but also within the DDU-ONLY and COMMI subgroups.

Why should positive outcome expectancies for substance use predict outcome in the reverse direction for the opiate addicts in this study compared with that found for nonaddicts (e.g., Stacy et al.. 1991) and for detoxified alcoholics (Brown, 19X5)? With respect to Stacy et al.‘s (1991) nonaddicts, whose expectancies for and subsequent LISC of alcohol and marijuana were assessed. the personal implications of positive outcome expectancies wcrc almost certainly quite diffcrcnt. in that there was no immediate sense of danger associated with the prospect of continuing current levels of substance use. When positive outcome expectancies interact with an awareness of personal vulnerability. they may impact on behaviour in a more complex way. There is. by contrast. no immediately obvious explanation for the reversal of Brown’s (19X5) findings with alcoholics, since the samples in both her study and in this one presented with long-term chronic dependence. One interesting possibility, however. is that the method used for assessing outcome expectancies is critical: whilst addicts in the present study indicated their perceived incentives for opiate use in the period immediately prior to detoxification, those in Brown’s study rated c7ntic.L

pr7rrtl reinforcements. WC may hypothesisc an inverse relationship between responses to the two forms of question, with subjects who are more highly motivated to remain abstinent being. on the one hand, more aware of incentives for their past behaviour and, on the other. less likely to anticipate those same drug effects being rewarding in the future. This possibility could be easily explored in a future study by administering both types of questionnaire to the same group of addicts.

Neither negative outcome expectancies (CONS). nor the difference between positive and negative expectancies (Motivational Balance), bore any clear relationships with outcome, either for the full sample or for any of the subgroups, except for a marginal effect for higher CONS score to be associated with a greater delay before first lapse in the DDU-ONLY sample. The failure of CONS to be related to outcome is surprising, since it seems likely, a priori. that negative outcome expectancies should increase motivation for abstinence. However. inspection of the frequency distributions of scores on the Motivational Checklist revealed that, whiist total PROS


scores followed a normal distribution, total CONS scores were heavily skewed to the right, with most subjects endorsing aversive consequences of drug use very highly. This is, perhaps, not surprising, since we might expect that individuals who have entered and completed an inpatient detoxification programme would indeed be acutely aware of a wide range of problems associated with drug use. It is possible, then, that the restricted range of scores, rather than the validity of the construct,

limited the predictive utility of the scale. The other variables which predicted days of opiate use at 6 months were scores on

the CQ, taken as an index of self-efficacy for remaining opiate-free. The CQI score (pretreatment) was predictive for DDU-ONLY subjects, and the CQ2 score (posttreatment) was predictive not only for the full sample but also for the DDU-ONLY and COMMZ subgroups. In all instances where correlations reached significance, lower scores (i.e., lower self-efficacy) were associated with fewer days of opiate use. Again, this conflicts with findings for alcoholics, where hi~lr self-efficacy predicted lower levels of drinking (Rist & Watzl, 1983: Solomon & Annis. 1990). As with outcome expectancies, then. it seems that in the present study, a greater awareness of personal vulnerability in terms of self-efficacy is beneficial. The possibility that the correlations achieved significance only by chance is a less viable interpretation than

for the PROS scores. Thus, correlations between CQ2 and opiate use at the second follow-up were significant at the 0.02 level (again using two-tailed tests), not only within the full sample, but also within both of the relevant subgroups (DDU-ONLY and COMMZ).

As with the data concerning the predictive status of PROS scores. it may be argued that addicts giving low self-efficacy ratings are more realistically attuned to potential threats to abstinence and accordingly are more likely to take protective measures. Consistent with this argument, PROS and self-efficacy scores were highly correlated with each other and did not make separate contributions to the overall variance in outcome. In connection with this interpretation, it has been reported elsewhere (Bradley, Gossop, Brewin, Phillips, & Green, 1992) that when addicts were asked. prior to inpatient detoxification, about the likely causes of any past and future lapses, those who acknowledged greater personal responsibility were significantly less likely to have relapsed 6 months after completing detoxification. Support for the relationship with application of protective measures in the present study is evident in the marked trend, falling just short of significance, for DDU-ONLY subjects with lower self-efficacy ratings to elect for further residential rehabilitation. Likewise. with BGW control subjects excluded, low posttreatment CQ scores were predictive of better outcome for those subjects who were in the community at 6 months. The pattern of results suggests that self-efficacy was a less potent predictor for the BGW groups than for the DDU groups. Whilst we can only speculate about the reasons for this, one possibility is that the shorter inpatient stay of the BGW subjects and their lower rate of discharge to residential rehabilitation means that they return to the community, with all its hazards of drug availability. in a particularly vulnerable state.

The relationship between self-efficacy ratings and outcome in this study was in the reverse direction to the relationship reported by Solomon and Annis (1990) with detoxified alcoholics, where higher self-efficacy was related to better outcome at 3 months. However, it should be noted that the association they reported was restricted to average amount of daily consumption and was not found for number of days of drinking. The relationship in the present study was with number of days of opiate use at 6 months, no such association being found with days of use at the more

488 J. POWELL et al

comparable first follow-up (average = 7.3 weeks): because of inherent difficulties in

ascertaining amount of opiates consumed. this outcome variable was not investi-

gated. Thus, there are no direct conflicts between results from the two studies. and it

may be that self-efficacy relates differently to different indicators of outcome and

that the form of the relationship varies over time. For example, lower self-efficacy

may plausibly be associated with greater avoidance of risk situations but consump-

tion of greater amounts of drug/alcohol once a lapse has occurred. Existing data are

intriguing. and future research may clarify whether there are underlying consistent

patterns.

None of the personality variables predicted days opiate of use at 6 months within

either the full sample or the subgroups, nor did they differentiate sub.jccts going on to

further residential rehabilitation from those returning to the community. However.

higher levels of neuroticism and trait anxiety wet-e both associated with longer sut-=

viva1 times before a lapse to opiate use in those subjects returning to the community.

Whilst it was hypothesised that highly neurotic and anxious subjects would be more

vulnerable to stress situations. and hence more likely to rclapsc early. it appears that

the relationship, in fact, operated in the reverse direction. A tentative explanation

may be that, in keeping with Gray’s (1982) model of personality. these subjects are

more scnsitivc to signals of impending stress and are consequently more alert to the

need to avoid risk situations: howcvcr, this can only bc vcrificd by further investiga-

tion. There was a weaker tendency for a longer delay before lapse in more impulsive

subjects returning to the community, again a counterintuitive relationship for which

there is no easy explanation and which requires verification.

Contrary to the predictions that certain personality traits would predispose to

lapsing in the context of specific precipitants, there was no evidence of this. Thus,

neurotic and anxious subjects were not more likely than their less neurotic or anx-

ious counterparts to report lapsing when in a negative emotional state or when

suffering interpersonal stress, nor was impulsivity associated with a tendency to

relapse in the contexts of direct or indirect social pressure, or when in an area

associated with drug use. It is, of course, possible that the absence of such relation-

ships reflects inaccuracy in the identification of relapse precipitants. here identified

retrospectively via a narrative account, and it would be interesting to repeat the

investigation using a checklist of possible triggers (cf. Heather et al., I991 1. so that

subjects systematically report on the presence or absence of a wide range of factors.

An even better, but practically very difficult, method would bc to interview subjects

immediately after their first lapse. However. the present results do at least caution

against making the assumption that certain types of person are susceptible to particu-

lar risk factors. Indeed, considering these results together with the findings that

lower self-efficacy and higher positive outcome expectancies were. in fact. pwtrc- tiuc factors indicates that subjective characteristics may relate to prognosis through

complex pathways which necessitate detailed empirical study rather than theoretical

inference.

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can opiate addicts tell us about their relapse risk? subjective predictors of clinical prognosis

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