Comorbid substance use disorders and mental health disorders among New Zealand prisoners

Along with the release of this report, a package of initiatives was announced on 14 June 2016 to add to existing mental health support in prisons.

Research shows that prisoners have high rates of mental health and substance use disorders. Because these individuals are less likely to seek help in the community, the disorders are often undetected or not treated properly. Mental health needs can be further complicated by other health needs such as substance use disorders, traumatic brain injuries or foetal alcohol syndrome. In the community, offenders with less acute issues have limited access to treatment options.

Corrections staff and contractors provide mental health treatment alongside general health services.

The Mental Health Screening Tool is part of the Initial Health Assessment and is carried out in the first seven  days after a prisoner arrives in prison. The screening is undertaken by a registered nurse. Prisoners are referred to Regional Mental Health Services if they screen as positive. If prisoners are found to have a primary mental health issue, they are treated in prison. Prisoners with a mild to moderate mental health need can be referred to a contracted provider for counselling (e.g. cognitive behavioural therapy) or other treatment.

Corrections currently spends $820,000 on packages of care at all prisons which provide support for around 500 prisoners a year, and on pilot in-reach positions at three prisons. Support is delivered to the prisoner and associated custodial staff to help manage the prisoner’s mental health needs within the prison environment. Medical officer hours, prescription costs and nurse time related to mental health services are part of the overall Corrections health budget.


A study of New Zealand prisoners conducted by the Department of Corrections in 1999 showed that up to 70 percent had drug and/or alcohol problems and a significant proportion had various mental health issues. However, that research didn’t consider the co-existence of mental health issues and drug/alcohol  problems, which overseas studies have identified as significant among prisoners.

Offenders are screened for drug and alcohol issues and mental health problems on reception to prison but, if problems are indicated, further assessments are conducted separately and the conditions are treated in parallel or serially. Understanding the extent of comorbidity is critical to providing the best possible treatment to the prisoner population. It is acknowledged that diagnosis of comorbid drug/alcohol problems and mental health issues can be difficult, as the symptoms related to drug use and those related to mental health disorders can be confused. In addition, the symptoms related to drug taking or mental health disorders may combine and reinforce each other when they appear, making it difficult to distinguish between the two.

In 2014, the Department successfully applied for funds from the Government’s Proceeds of Crime allocation under the Methamphetamine Action Plan to conduct a study into the prevalence of co-morbid mental health and substance abuse issues amongst prisoners. National Research Bureau was contracted to interview prisoners about substance use and mental health problems, and CGA Consulting was contracted to analyse the data collected and to produce a report summarising the findings.

Over 1200 prisoners were interviewed across 13 prisons between March and July 2015 and this report presents the findings from those interviews.

The results will enable the Department to work with the Ministry of Health to improve planning for service delivery across the health and corrections domains; they will support improved delivery of forensic mental health services within prisons; and they will assist the Department in assessing prisoners and ensuring that all forms of treatment, both psychiatric and rehabilitative, are delivered in an integrated way.

Download the full study: Comorbid substance use disorders and mental health disorders among New Zealand prisoners (pdf. 3 MB)