Forensic aspects of psychiatry

Forensic aspects of psychiatry
Associations between psychiatric disorders and crime
Possible relationships between crime and mental disorder
1. coincidence
2. correlation
3. cause
· among male sentenced prisoners in England and Wales
· 37 % have diagnosable disorder
· 0.6 % have mental retardation
· 2 % have psychosis
· 6 % neurotic disorder
· 10 % personality disorder
· 12 % alcohol dependence
· 12 % drug dependence
· convicted prisoners:
· 5.2% major psychological disorder (Cooke 1994)
· remand prisoners:
· 2.3% major psychiatric disorder (Davidson et al. 1995)
· 14.1% depression
· 10.8% anxiety and agitation
· 22.4% alcohol problem
· 70% had abused drugs
· the disorders most likely to be associated with crime are:
· personality disorders
· alcohol and drug dependence
· mental retardation
State Hospital admission
· factors precipitating admission:
· alcohol or drug intoxication 21.2%
· non-compliance with medication and relapse 11.2%
· psychosis 54.8%
· ‘normal’ aggression 15.4%
Important studies
1. Hafner & Boker, 1982
· all homicides and attempted homicides in West Germany 1955-64
· mental disorder was associated with 5% of these
· the rate of mental disorder in the community was 3-5%
· homicidal violence rateschizophrenia = 5/10,000
· schizophrenics were 100x more likely to commit suicide than
homicide
· homicidal violence rateaffective disorder = 6/100,000
· affective disorders were 1000x more likely to commit suicide than
homicide
2. Swanson et al. 1990 ‘Violence and psychiatric disorder in the community:
evidence from the epidemiological catchment area survey’
· violence in last 12 months:
· non-substance use schizophrenia 8.3%
· substance abuse 21%
· substance abuse schizophrenia 30%
· active psychotic symptoms are associated with an increased risk of violence
Patterns of offending
· peak age of offending is:
· 14 in girls; there is another peak around the menopause
· 17-18 in boys
· 50% of all indictable crimes are committed by people under the age of 21
· the sex ratio of convicted men to women is approximately 5:1
· by the age of 30, around 30% of men have been convicted of an indictable offence