ESSAY QUESTION: Offenders commit crimes because they are mentally ill
Two types of evidence:
1. Prevalence of mental illness in criminal populations
2. Prevalence of crime in psychiatric populations
1. Prevalence of mental illness in criminal populations
Gunn et al. (1978)
Assessed the psychiatric status of a sample of 600 offenders.
One in five had a marked or severe psychiatric condition - mostly depressed / anxiety (could
be a reaction to imprisonment)
Drugs and alcohol addiction quite high
Seldom SZ
Old study
Taylor (1966)
2/3 of prisoners serving life sentences were psychiatrically disturbed
Old study
Wallace et al. (1998):
Investigated those convicted in the higher courts of Victoria, Australia, between 1993-1995
Looked at their psychiatric histories
Prior psychiatric contact found in 25% of offenders, mainly personality disorders / substance
abuse
Conclude the increased offending in SZ / affective illnesses is modest & may be mediated by
substance misuse.
Men with SZ who also had a record of substance misuse were over 8 x more likely to appear
among violent offenders and 4 x more likely to be convicted of homicide than those without
comorbid substance abuse
The case register may give a selected / potentially skewed sample of those with affective
disorders, personality disorders and substance misuse disorders.
Copeland et al. (2007):
Large community based sample of youths
About 1/3 met criteria for mental disorders at one or more of the 3 childhood assessment
points
About 1/3 of the population was arrested in young adulthood (16-21 aged)
Within this arrested sample, ½ of males and under ½ females met criteria for mental disorders
assessment points before 17
Not causal
Many of the youths with mental disorders as children did not offend
, Found emotional disorders like depression were less relevant to later offending than
behaviour disorders or substance use.
But adolescent emotional disorders comorbid with substance use is by far the greatest risk of
future adult offending.
Copeland et al conclude that mental disorders offer only one possible path to later criminality
and it does not appear to be the most frequently followed path.
Schizophrenia
Spry (1984)
Reviewed the evidence and noted that the incidence of SZ in offender populations is around
1%, unless looking at prisoners referred for psychiatric treatment or for violent serious
offences
Taylor (1985):
In 1/5 of cases, psychiatric symptoms played a role in the offence. When environmental
factors are taken into consideration the direct and indirect consequences of psychosis - over
80% of offences by the psychotic are not attributable to their illness
Depression
Ritakallio et al. (2005)
50,599 (v large sample) Finish adolescents
Surveyed for delinquent behaviour and depression
BDI but suicide ideation removed for ethical reasons – too young sample
Self report of delinquent behaviour
Representative sample - urban and rural municipalities of different sizes
Fulfils a need for research in general population - only 10% of offenders are incarcerated yet
most research looks at incarcerated
Delinquency and depression were related
Risk of depression increased with more delinquent behaviour
Probably under-assessment as don’t want to admit to delinquency in school setting - self
report in front of teachers - probably thought teachers would read
Weisner (2003):
Longitudinal - 4 waves
1,218 males and females - few other studies have focused on gender differences
Relationship between delinquency and depression
90% sample retention - v. Good
In boys, limited results - the association was uni-directional - high levels of delinquency @
Time 3 predicted high depression, but small effect
In girls, larger but still modest effects, bi-directional. High delinquency @ T 1 & T3 predicted
high subsequent depression, high depression @ T1 predicted high subsequent delinquency
Circular - due to gender socialisation - not allowed to be delinquent - so shame and guilt and
depression
Limitations: all suburban schools, middle class Caucasian
Two types of evidence:
1. Prevalence of mental illness in criminal populations
2. Prevalence of crime in psychiatric populations
1. Prevalence of mental illness in criminal populations
Gunn et al. (1978)
Assessed the psychiatric status of a sample of 600 offenders.
One in five had a marked or severe psychiatric condition - mostly depressed / anxiety (could
be a reaction to imprisonment)
Drugs and alcohol addiction quite high
Seldom SZ
Old study
Taylor (1966)
2/3 of prisoners serving life sentences were psychiatrically disturbed
Old study
Wallace et al. (1998):
Investigated those convicted in the higher courts of Victoria, Australia, between 1993-1995
Looked at their psychiatric histories
Prior psychiatric contact found in 25% of offenders, mainly personality disorders / substance
abuse
Conclude the increased offending in SZ / affective illnesses is modest & may be mediated by
substance misuse.
Men with SZ who also had a record of substance misuse were over 8 x more likely to appear
among violent offenders and 4 x more likely to be convicted of homicide than those without
comorbid substance abuse
The case register may give a selected / potentially skewed sample of those with affective
disorders, personality disorders and substance misuse disorders.
Copeland et al. (2007):
Large community based sample of youths
About 1/3 met criteria for mental disorders at one or more of the 3 childhood assessment
points
About 1/3 of the population was arrested in young adulthood (16-21 aged)
Within this arrested sample, ½ of males and under ½ females met criteria for mental disorders
assessment points before 17
Not causal
Many of the youths with mental disorders as children did not offend
, Found emotional disorders like depression were less relevant to later offending than
behaviour disorders or substance use.
But adolescent emotional disorders comorbid with substance use is by far the greatest risk of
future adult offending.
Copeland et al conclude that mental disorders offer only one possible path to later criminality
and it does not appear to be the most frequently followed path.
Schizophrenia
Spry (1984)
Reviewed the evidence and noted that the incidence of SZ in offender populations is around
1%, unless looking at prisoners referred for psychiatric treatment or for violent serious
offences
Taylor (1985):
In 1/5 of cases, psychiatric symptoms played a role in the offence. When environmental
factors are taken into consideration the direct and indirect consequences of psychosis - over
80% of offences by the psychotic are not attributable to their illness
Depression
Ritakallio et al. (2005)
50,599 (v large sample) Finish adolescents
Surveyed for delinquent behaviour and depression
BDI but suicide ideation removed for ethical reasons – too young sample
Self report of delinquent behaviour
Representative sample - urban and rural municipalities of different sizes
Fulfils a need for research in general population - only 10% of offenders are incarcerated yet
most research looks at incarcerated
Delinquency and depression were related
Risk of depression increased with more delinquent behaviour
Probably under-assessment as don’t want to admit to delinquency in school setting - self
report in front of teachers - probably thought teachers would read
Weisner (2003):
Longitudinal - 4 waves
1,218 males and females - few other studies have focused on gender differences
Relationship between delinquency and depression
90% sample retention - v. Good
In boys, limited results - the association was uni-directional - high levels of delinquency @
Time 3 predicted high depression, but small effect
In girls, larger but still modest effects, bi-directional. High delinquency @ T 1 & T3 predicted
high subsequent depression, high depression @ T1 predicted high subsequent delinquency
Circular - due to gender socialisation - not allowed to be delinquent - so shame and guilt and
depression
Limitations: all suburban schools, middle class Caucasian
