neurobiology of psychopathic behavior
TRANSCRIPT
Neurobiology of Psychopathic behavior
Subhadeep Dutta Gupta
The lack of baggage and fear
Introduction• The word ‘personality’ refers to the pattern of thoughts, feelings and behaviour
that makes each of us the individuals that we are
• Personality doesn’t change very much, but it does develop as we go through
different experiences in life, and as our circumstances change. So, as we mature
with time, our thinking, feelings and behaviour all change
• Personality disorders (PDs) are considered chronic conditions that emerge in late
adolescence, and typically carry pervasive implications for self- and/or
interpersonal functioning (American Psychiatric Association [APA], 2013; Skodol,
2012)
Classification of Personality Disorders:
Historical Overview:
• First described a group of patients afflicted
with mania sans délire (insanity without
delirium)
• The term was used to describe individuals
who had no intellectual problems but a
profound deficit in behaviour typified by
marked cruelty, antisocial acts, alcohol and
drug use, irresponsibility, and immorality
Philippe Pinel (1745-1826)
Julius Koch (1841-1908)
• Coined the term psychopastiche, or
psychopath, in 1888
• Koch claimed that psychopathy arose
from a flaw in one’s constitution at birth
Historical Overview:
Diagnostic Criteria for Antisocial Personality Disorder in DSM-V:
1. Failure to obey laws and norms by engaging in behaviour which results in
criminal arrest, or would warrant criminal arrest
2. Lying, deception, and manipulation, for profit or self-amusement
3. Impulsive behaviour
4. Irritability and aggression, manifested as frequently assaults others, or
engages in fighting
5 Blatantly disregards safety of self and others
6 A pattern of irresponsibility and
7. Lack of remorse for actions (American Psychiatric Association, 2013)
Who are Psychopaths?• Conduct disorder is a childhood behaviour disorder that is characterized by
persistent aggressive or antisocial behaviour that disrupts the child’s environment
and impairs his or her functioning – Macdonald Triad
• Psychopathic traits consist of a callous–unemotional component and an
impulsive–antisocial component, which are associated with two core
impairments:
reduced empathic response to the distress of other individuals;
deficits in decision making and in reinforcement learning
• Empathy: ‘‘An affective response more appropriate to someone else’s situation
than to one’s own’’ (Hoffman, 1987)
• Callousness: Omission of caring feelings or behaviours in contexts where others
generally experience those feelings or behaviours
Brain regions associated with experience sharing and mentalizing
-- Nature Neuroscience 15, 675–680 (2012)
Traits of a Psychopath:• repeatedly engages in a wide range of irresponsible, unethical or criminal activities
for personal gain
• has a constant need for stimulation and lacks any realistic long term goals
• lacks empathy or remorse and tends to blame others for his unscrupulous activities
• will appear superficially charming, but also glib and shallow with a grandiose sense
of self-worth
• promiscuous sexual behaviour, many short-term marriages, adultery and so forth
are common
Snakes in suits:• Across all races, cultures and ethnic groups ; Male : Female 4:1
• 1% of general population aged 18 and above and 10-20 % of prisoners
• Most psychopaths as : Least psychopaths as:
• It is twice as common as schizophrenia, anorexia, bipolar disorder, and paranoia
• Recidivism 4-8 times the rate compared to other offenders
CEO
Lawyer
Media (T.V / Radio)
Salesperson
Surgeon
Journalist
Police officer
Care aide
Nurse
Therapist
Craftsperson
Beautician
Charity worker
Teacher
Types:• Primary Psychopathy:
constitutional deficit that leads to callous and manipulative behaviour,
superficial relations, and a lack of negative affect such as guilt, fear or anxiety;
they plan their behaviour and socially rank themselves higher than others
• Secondary Psychopathy:
develops from environmental causes, such as parental abuse or rejection,
resulting in an underlying emotional problem associated with neuroticism,
impulsivity, aggression and emotional reactivity
Evolution of Psychopathy Frequency- dependent selection:
Psychopaths have evolved to take the advantage of the fact that most people
are cooperators
Thus psychopathy represents an alternative strategy that is successful only at a
particular low relative frequency in the population
If there are too many cheaters , non-psychopaths become very vigilant and
cheating opportunities disappear
Theoretical Basis for
Psychopathy
Neurobiological Theory:
Phineas Gage (1823-1860) Gage’s skull and the tamping iron on display at the
Warren Anatomical Museum
Neural underpinnings of empathy & callousness
The Social Brain:• Empathy connects neurocircuitry for social behaviour, physical pain, and the
ability to represent both the self and another
• Functional neuroimaging studies in humans document a Empathy Circuit
including :
Anterior insula
Anterior cingulate cortex
Supplementary motor area
Amygdala
Brainstem
Periaqueductal gray – that responds to the perception of others’ distress
Role of Cortex :
• The prefrontal cortex is an area of the brain that is important for reasoning,
inhibition of behaviour, social emotions, empathy, attention, and executive
functions
Mirror ‘Gandhi/ Dalai Lama’ Neuron System
Orbitofrontal Cortex (OFC)
Ventromedial Prefrontal Cortex (vmPFC)
Anterior Cingulate Cortex (ACC)
-- Nature Medicine 18, 211–213 (2012)
Role of vmPFC:
connecting past decisions or outcomes with new decisions one might be
considering/ contemplating (e.g., pursuing a reward). This includes involvement
in extinguishing past behaviours and learning from experience
strongly associated with assigning value to an action or goal of a certain
behaviour or decision. This assists in the process of making a choice between
different rewards by weighing which would be better
regulating role within the emotional (limbic) system of the brain. Therefore, it is
suspected to be involved in the control or regulation of emotions, notably
negative emotions
enables individuals to adapt their behaviour in response to unexpected rewards
or adversities
enables individuals to anticipate whether some course of action will evoke
positive or negative emotions, both immediately and in the future
when the OFC is activated, individuals choose the courses of action that tend to
be rewarded, rather than punished, by other people
OFC facilitates the Theory of Mind capacity – Affective ToM
Role of OFC:
-- Brain and Cognition 2004 ;55 (1) 198–208
• Unique position in the brain, with connections to both the “emotional” limbic system and
the “cognitive” prefrontal cortex
• empathy for pain activates neural structures that are also involved in the direct experience
of pain—such as the anterior insula and the ACC
• Detection of errors
• Detection of conflicts
• Reward based learning Theory
• Emotional regulation
Role of ACC:
Von Economo neuron Pyramidal neuron
Low activity in depressed subjects
High activity in normal subjects
recollecting sad events
--Principles of Neural Science, 5th Edn
The Psychopathic Brain
Prefrontal lesions can lead to a form of acquired psychopathy
1. Cortical Abnormalities:
Pattern of percent gray matter local difference (left panel) and statistical
significance (right panel) of the cerebral cortex in psychopathy versus controls
-- Psychiatry Research: Neuroimaging 193 (2011) 85–92
Reduced PFC gray matter volume and reduced Autonomic activity in Psychopaths
PFC Gray matter volume Heart Rate
PFC White matter volume Skin conductance
-- Arch Gen Psychiatry 2000 (57), 119–127
vmPFC dysfunction:Focal vmPFC lesions
personality changes (lack of empathy, irresponsibility,
and poor decision making)
Pseudopsychopathy
Uncinate Tract
n = 9 (each group)
p = 0.003
-- Molecular Psychiatry (2009) 14, 946–953-- Developmental Cognitive Neuroscience 14 (2015) 50–61
Reduced Prefrontal Metabolism in Psychopaths
Control Psychopath
Illustration of cortical deficits in one psychopath (right) relative to one control (left)
Prefrontal gyri/occipital ratios for cortical peel technique.
-- Biol Psychiatry 1994 (36) 365-373
n = 22
2. Limbic Dysfunctions:
• Amygdala
• Hippocampus
Amygdala:• Amygdala deals with emotion, memory, fear, anger, and pleasure
• Reward learning, social interaction, and moral emotion and reasoning, where
the ability to recognize the emotions signalled by facial expressions is crucial
for making advantageous decisions in a complex social environment
• Evidence from Kluver – Bucy Syndrome
-- Arch Gen Psychiatry. 2009; 66(9): 986–994
Psychopathic individuals were found to
show bilateral amygdala volume
reductions compared with controls.
n = 86
-- J Abnorm Psychol. 2010; 119(4): 863–874.
n = 16
Positive association between right
amygdala activity and violation severity
ratings present in nonsychopaths
Deformations within the Amygdala in Psychopaths
Regional atrophy in amygdala structure in the vicinity of the basolateral, lateral,
central, and cortical nuclei in individuals with psychopathy
-- Arch Gen Psychiatry. 2009 Sep; 66(9): 986–994
Hippocampus
-- Human Brain Mapping 31:438–447 (2010)
Unsuccessful psychopaths have an exaggerated structural asymmetry
in the anterior hippocampus.
-- Biol Psychiatry 2004;55:185–191
3. Basal Ganglia Dysfunctions:
-- Behavioural Brain Research 169 (2), 2006, 239–247 -- Biol Psychiatry 2010;67(1):52-8
4. Cerebellar Dysfunctions:
Positive regression within prisoners between scores of Factor 1 (PCL-R) and
gray matter volume of the right cerebellar hemisphere.
-- Neuroscience Volume 308, 12 November 2015, Pages 194–201
Control = 40Psychopaths = 37
5. Corpus Callosum
-- Arch Gen Psychiatry. 2003;60(11):1134-1142
Neurochemistry of
Psychopathic Brain
Role of Cortisol and Testosterone:
HPA and HPG maintain an appropriate balance between withdrawing in the presence of
fearful or threatening stimuli, and approaching in the presence of rewarding stimuli
Average salivary cortisol (lg/dl) levels by group and gender
Males Females
16
13
11 15
9
1416
14
-- Journal of Child Psychology and Psychiatry 47:1 (2006), pp 30–36
Testosterone shifts the balance between sensitivity for punishment
and reward in healthy young women
-- Psychoneuroendocrinology, Volume 29, Issue 7, 2004, 937–943
High testosterone/cortisol ratio
communication between emotional (sub-cortical, amygdala) and cognitive (cortical,
OMPFC) systems is diminished
emotional information from the amygdala cannot adequately reach the cortex, and
therefore cannot be used to avert the basic motivational, reward driven
reactions
violence inhibition mechanism doesn't function properly
Salivary α- amylase:
Males scoring low in psychopathy demonstrated a significant increase in sAA
levels following the social stress task whereas individuals scoring high in
psychopathy did not
-- Psychoneuroendocrinology, Volume 54, 2015, 14–23
n = 158
Electrophysiological difference
in Psychopathy
-- Psychophysiology, Volume 28 (3), 1991
Neurogenetics and
Psychopathy
Role of SNAP-25 gene:
MnlI T/T and DdeI T/T genotypes were more frequently present in male subjects with
APD than in controls
-- Can J Psychiatry. 2011 Jun; 56(6): 341–347
MAOA gene is knocked out in mice
highly aggressive, becoming ‘‘knock-out’’ fighters themselves
Knock the gene back in, and they return to their normal behaviour patterns
(Cases et al., 1995)
Role of MAO-A gene:
-- Science 297, 851 (2002)
Summary
Insane isn’t really black or white, we are all pathological, in our own ways