# Imprisonment and mortality among adults with neurodevelopmental disabilities in New South Wales, Australia, 2001–2015: a data-linkage cohort study

## TL;DR

People with neurodevelopmental disabilities who were released from prison had higher mortality rates, but this was largely due to health issues like mental illness and substance use.

## Contribution

This study is the first to examine mortality risks among adults with neurodevelopmental disabilities following imprisonment in Australia.

## Key findings

- Release from prison was associated with higher mortality in adults with neurodevelopmental disabilities before adjusting for health factors.
- Being known to prison disability services was linked to higher post-release mortality, while community services were not.
- Health-related factors like mental illness and substance use largely explained the increased mortality after prison release.

## Abstract

(1) Examine the associations between imprisonment history and mortality among adults with neurodevelopmental disabilities and (2) examine the associations between receipt of disability services and post-release mortality among adults with neurodevelopmental disabilities released from prison.

Population-based data-linkage cohort study using historical administrative data.

New South Wales (NSW), Australia.

67 217 adults aged ≥18 years (59.1% male) with one or more neurodevelopmental disabilities in NSW, Australia, from July 2001 to June 2015.

The main outcome measure was all-cause mortality. In the full cohort, we used Cox regression to examine the associations between release from imprisonment and all-cause mortality. In a subcohort of those released from prison, we used Poisson regression to examine the associations between receipt of disability services and post-release all-cause mortality.

3.3% of participants (n=2214) were imprisoned and released at least once during follow-up. In all age groups<55 years, age-specific all-cause mortality rates were higher in those released from prison than in those who were not imprisoned. In Cox regression models, after adjusting for sociodemographic factors, release from prison was associated with higher all-cause mortality compared with never imprisonment (adjusted HR (aHR) 1.50 (95% CI 1.17 to 1.92)); however, this association was no longer present after further adjustment for mental illness, substance use and physical comorbidity (aHR 1.02 (95% CI 0.79 to 1.31)). Among those released from prison, being known to the prison disability service was associated with higher post-release mortality (adjusted mortality rate ratio (aMRR) 1.97 (95% CI 1.18 to 3.30)), whereas receipt of community disability services was not associated with post-release mortality (aMRR 1.09 (95% CI 0.55 to 2.15)).

Among adults with neurodevelopmental disabilities, mortality was increased among those released from prison compared with their peers who had not been imprisoned, although this was largely explained by health-related factors, including mental illness, substance use and physical comorbidity. Comprehensive policy and service system responses are required to meet the health and safety needs of people with neurodevelopmental disabilities who have complex needs, including criminal legal system involvement, mental illness and substance use.