Abstinence Incentive Effects in Psychosocial Counseling Patients Testing Stimulant

Positive vs Negative at Treatment Entry

Maxine L. Stitzer

Johns Hopkins Univ SOM

National Drug Abuse Treatment Clinical Trials Network MIEDAR Study Team

Background CTN Motivational Incentives Study

• Incentive therapies offer reinforcers for therapeutically desirable behavior change

• Abstinence incentives have a strong evidence-base from small-sample efficacy research across a range of abused substances (stimulants, opiates, alcohol, marijuana)

• National Drug Abuse Treatment Clinical Trials Network multi-site effectiveness study– 8 psychosocial counseling community clinics

– N = 415 stimulant abusers; cocaine or methamphetamine

Background CTN Motivational Incentives Study

• “Fishbowl” method offered drawings for prizes based on stimulant-negative urines; max earnings = $400

• Random assignment to usual care with or without incentives over 12-week evaluation

• Prize-based incentives found effective for stimulant abusers enrolled in community drug abuse treatment– Improved retention in psychosocial counseling

• Petry et al., Arch Gen Psychiat, Oct, 2005– Reduced stimulant drug use in methadone maintenance

• Peirce et al. Arch Gen Psychiat, Feb. 2006

Background• Regression analysis conducted to identify

outcome predictors

• Stimulant urine test result (pos/neg) at study entry emerged as strongest predictor of response to incentive procedure (R2 = .26)

Objective

• Examine overall impact of intake stimulant urine test result on treatment outcome

• Determine whether incentive effects differ for those who enter the study with stimulant positive vs negative urines

Methods

• Grouping variable = first study urine stimulant positive vs negative– Stimulant = both cocaine & methamphetamine– Psychosocial counseling patients were new

clinic intakes

MethodsOutcome measures examined

A) Study retention - time to last urine sample provided prior to 30-days

with no contact

B) Percent submitted samples stimulant negative twice weekly data collection

Data analysis– Survival (A)– GEE (B) for main effects of group (stim pos/neg) and

interaction of study treatments with intake urine

RetentionP

erce

ntag

e R

etai

ned

100

80

60

40

20

0

0 1 2 4 5 7 9 11 1210863

Stimulant Negative (n = 306)Stimulant Positive (n = 108)

Study Weeks

At study intake:

HR =1.71 (1.26-2.31)

Retention

HR = 1.86 (1.35-2.56) HR = 1.19 ns

Study Week Study Week

100

80

60

40

20

0

100

80

60

40

20

0

Stimulant Negative (n = 306) Stimulant Positive (n = 108)

IncentiveUsual Care

IncentiveUsual Care

42 6 8 10 12 42 6 8 10 12

Per

cent

age

Ret

aine

d

2 6 8 10 12

0

20

40

60

80

100

4 2 6 8 10 12

0

100

4

20

80

40

60

Stimulant Negative (n = 306) Stimulant Positive (n = 108)

Study Weeks Study Weeks

IncentiveUsual Care

IncentiveUsual Care

Per

cent

age

of S

ampl

esS

timul

ant N

e gat

ive

Stimulant Drug UsePercent submitted samples stimulant negative; missing urines considered missing

100

80

60

40

20

0

2 4 6 8 10 12

100

80

60

40

20

0

2 4 6 8 10 12

Study Week Study Week

Stimulant Negative (n = 306) Stimulant Positive (n = 108)

IncentiveUsual Care

IncentiveUsual Care

Stimulant Drug Use Percent submitted samples stimulant negative; missing urines considered positive

OR = .95(0.51-1.77)

OR =1.90(1.4 - 2.6)

Summary: Main Effect of Initial Urine Test Result

• Stimulant positive at study entry confers a poor outcome prognosis– consistent with prior research (e.g Alterman et al.,

1996, 1997; Ehrman et al., 2001; Sofuoglu et a., 2003)

Summary: Interaction of Incentives with Initial Urine Test Result

• Improved retention in psychosocial counseling only for those stimulant negative at study start– Limited opportunity for stimulant positive to

contact reinforcers?

Treatment Implications

• Importance of initial urinalysis results in psychosocial counseling programs

• Implications for treatment selection– Incentives for counseling patients entering tx stimulant

negative– Special treatment (not abstinence incentives) for

counseling patients entering tx stimulant positive

Acknowledgements

• NIDA CTN for funding• MIEDAR study team for successful conduct of the

multi-site study• Jessica Peirce for prediction analysis • Ken Kolodner and Rui Li for statistical support;

Joe Harrison for graphics