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Offending behaviour and drugs/alcohol, mental health and cognitive impairment

There is often a strong link between offending behaviour of people in contact with the criminal justice system and drugs/alcohol, mental health and cognitive impairment.

Drug and alcohol use and offending behaviour

The NSW Inmate Health Survey (Indig et al 2010a) demonstrates the strong link between offending behaviour and alcohol and drug use. While most offences were not, strictly speaking, 'drug related' by definition (11% were convicted of drug offences), a large proportion of prisoners were intoxicated at the time of their offence (61%), believed their substance use was related to their current sentence (54%) and had high rates of illicit drug use and problematic drinking.

The following figure shows the high rates of illicit drug use and hazardous or harmful drinking in the NSW prison population.

Alcohol and illicit drug trends in NSW prisoner population

Illicit Drug Trends

Alcohol Use Trends
Source: Indig et al (2010a).

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Mental health of criminal justice clients

Psychiatric disorders identified in the Australian prison population are substantially higher than in the general community. In 2006, the 12-month prevalence of any psychiatric illness in the last year was 80% in prisoners compared with 31% in the community (Butler et al 2006).

The 2009 Inmate Health Survey noted that almost half of participants reported they'd been assessed or had received treatment for a mental health problem, with approximately one-fifth of participants currently on psychiatric medication.

The following figure shows the mental health disorders in the NSW prison population, which range from serious mental illness to chronic depression, with the most common diagnosis for both sexes being depression (Indig et al 2010a).

Mental health disorders in the NSW prison population

Mental Health Disorders in NSW Prison population
Source: Indig et al 2010a.

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Criminal justice clients and cognitive impairment

People with a cognitive impairment are significantly more likely to have contact with the criminal justice system from an earlier age, and those with a cognitive impairment or mental health issue are also more likely to have a co-existing substance use disorder (Baldry et el 2011).

People with an intellectual disability are overrepresented in the criminal justice system and are more likely to:

  • Be arrested
  • Be questioned and detained for minor public offences
  • Receive harsher penalties
  • Have less access to sentencing options
  • Experience disadvantage when interviewed by police or when in court because they may not understand what's happening and what's being said
  • Be highly vulnerable in prisons because of their disability
  • Have higher rates of reoffending than the general population.

While limited research is available, people with other forms of cognitive impairment may experience similar higher contact with the criminal justice system.

You should be aware that people entering your service with a long history of contact with the criminal justice system may have a cognitive impairment and that a formal diagnosis or assessment history is not necessarily going to be available.

The Criminal Justice Support Network of the Intellectual Disability Rights Service can show you how to support people with intellectual disability (diagnosed or suspected) who are in contact with the criminal justice system. Visit www.idrs.org.au

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Find out more

NSW Ombudsman (2008) Supporting People with an Intellectual Disability in the Criminal Justice System: Progress Report, Sydney.

Intellectual Disability Rights Council (IDRS) (2012) Step By Step Guide To Making A Section 32 Application For A Person With An Intellectual Disability, Sydney.

arbias & La Trobe University (2010) Acquired Brain Injury: Screening, Identification and Validation in the Victorian Correctional System, La Trobe University.

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