Mental Disorder & Crime


Legal Definitions Of Mental Illness

Mental Health Act (1983) - 4 legal categories of mental disorder included: mental illness, psychopathic disorder, mental impairment & severe mental impairment

Mental Health Act (2007) -  "any disorder or disability of the mind"

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Other Key Terms & Legal Issues


Mental illness

'Legal insanity'

"In law, the term is used to denote that degree of mental illness which negates the individual's legal responsibility or capacity" - Black's Law Dictionary (1990)

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Legal Prerequisites Of Crime

To be found guilty of a crime, one must have not only carried out the act of crime but have intended to commit that crime



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Legal Pleas

1. Not guilty by reason of insanity (NGRI) - courts appy the 'McNaghten rule'

2. Diminished responsibility (Homicide Act, 1957) - must be proof of 'substancially impaired mental responsibility'

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Mental Health Problems In Prison (Singleton Et Al

Psychosis - prison 6-13%, general 0.4%

Personality disorder - prison 50-78%, general 3.4-5.4%

Neurotic disorder - prison 40-76%, general 17.3%

Drug dependency - prison 34-52%, general 4.2%

Alcohol dependency - prison, 19-30%, general 8.1%

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Relationship Between Mental Disorder & Crime Sensa

Over reporting of high profile cases & over reporting of relationship (Angermeyer & Shulze, 2001)

Specific types of mental health difficulties are over represented:

1. Schizophrenia

2. Learning difficulties

3. Depression

4. Psychopathic disorder

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Difficulties With Research (Howitt, 2006)

Possible confounds - over emphasis on correlational studies?

Overlapping definitions

Confounding effects of medication

Difficulties in identifying a sample

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Mental Disorder In Offender Populations & Issues

30-50% have mental illness/disorder compared to 14% of non-offenders (Howitt, 2009)

Up to 60% 'lifers' are disordered

If we include psychopathic disorder - up to 80%


Caught more often?

Charged more often?

Plead guilty more often?

Effects of prison?

Cumulative effects?

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Criminality In Mentally Ill Populations & Issues

6% criminality as opposed to 2% (Hodgins, 1995)

Sufferers of psychotic symptoms in community more likely to be violent - up to 14x more?


Small sample sizes amongst in patients

Environmental effects particular issue with community based studies

Status of discharged patients unclear - still 'disordered' or not?

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Unselected Birth Cohorts: SMP (Hodgins, 1995)

Over 14,000 births followed with independent secondary verification of diagnoses of:

1. Major mental disorder

2. Minor mental disorder

3. Alcohol & drug abuse


Biggest 'risk' factor is substance abuse

Co-morbidity - 49% males % 43% females had secondary diagnoses

Lack of distinction between use & abuse at time of arrest

No picture of cause & effect

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Psychopathic Disorder

Psychopathy is a personality disorder that may be confused with adult antisocial personality disorder (AAPD)

50-80% of prison inmates meet AAPD criteria, only 11-25% meet a set of more specific criteria (Hare, 1998)

Hare (1993) suggests 3 categories of psychopath:

1. Primary psychopath - diagnosed through PCL

2. Secondary psychopath - antisocial/violent behaviour due to emotional problems, anxiety, drug use etc

3. Dissocial psychopath - learned aggressive & antisocial behaviour

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Problems With Hare's Categories Of Psychopath

Definition is controversial

Not specifically defined in ICD-10 or DSM-V

Closest is antisocial personality disorder (dissocial)

Higher scorers on PCL-R often begin their criminal careers earlier & more likely to reoffend

Clinical psychopathy (measured by the PCL-R) is quite different to legal classification of 'psychopathic disorder'

Psychopathic disorder referred to in the mental health act (1983) as any personality disorder, not just psychopathy

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Hare's Psychopathy Checklist (PCL)

Measures 2 main factors:

1. Affective deficits - considered the most powerful indicator

2. Behavioural problems

Cooke & Mitchie (2001) suggest 3 factors are identifiable - the addional one being interpersonal style

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PCL Based On Cleckley's Traits

Egocenticity & flat effect

Pathological lying

Unreliability, irresponsibility, impulsivity

Inability to feel remorse, empathy, or understand consequences for others

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Criminal Psychopaths

Hare (1993) - up to 25% in prison, compared to 1% out of prison

Up to 43% of serial r*pists

Bartol & Bartol (2004) - more likely to have convictions for violence & be associated with violence in prison

Recividism rate of between 65-80%, compared to 30-50% non-psychopathic adult offenders

Recidivism rates rise after 'treatment'? - learn

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Treatment Of Criminal Psychopaths (Hare, 1996)

There is no known treatment for psychopathy - but doesn't mean that the egocentric & callous attitudes & behaviours are immutable

No methodologically sound treatments or 'resocialisation' programmes that have shown to work

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Summary Of Risk Factors (Hodgins, 1995)

MD alone in adulthood - 2.5x

MD & substance abuse in adulthood - 6.1x

MD & substance abuse in childhood - 14.1x

Early start group again at most risk:

1. Convicted on average 5 years earlier

2. More likely to suffer co-morbidity

3. More likely to have both violent & non-violent convictions

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