# Temporal relationships between incarceration and mental disorders among justice-involved adolescents: A population-based cohort study

## TL;DR

This study finds that mental disorders increase the risk of incarceration and that incarceration increases the risk of mental disorders in adolescents.

## Contribution

The study provides new evidence on the bidirectional relationship between incarceration and mental disorders in justice-involved adolescents.

## Key findings

- Pre-existing mental disorders were linked to a 26% higher incarceration risk.
- Incarceration was associated with a 22% higher risk of new mental disorder diagnoses.
- Stronger associations were observed in adolescents with violent offenses and those in disadvantaged areas.

## Abstract

To determine bidirectional relationships between incarceration and mental disorders. We hypothesized that (1) pre-existing mental disorders would be associated with increased incarceration risk, and (2) incarceration would be associated with increased incident mental disorder diagnosis risk in adolescents without prior psychiatric diagnosis.

This retrospective cohort study included 1551 adolescents (aged 10–17 years) from four New South Wales (NSW) health surveys linked to justice and health records. Modified Poisson regression examined associations between pre-existing mental disorders and incarceration. Prentice-Williams-Peterson Total-Time models examined associations between time-varying incarceration exposure and incident mental disorder diagnoses among those without prior diagnosis.

Among 1551 adolescents (87.7% male; median age 15 years), pre-existing mental disorders were associated with an increased incarceration risk (adjusted Risk Ratio [RR]: 1.26, 95% Confidence Interval [CI]: 1.09–1.45), which was more pronounced among those with violent offences. Among 1424 adolescents without prior diagnosis, incarceration was associated with increased incident diagnosis risk (adjusted Hazard Ratio [aHR]: 1.22, 95% CI: 1.09–1.37), with stronger associations among adolescents residing in areas of higher socioeconomic disadvantage.

Findings suggest incarceration may be associated with adverse mental health outcomes, with implications for diversionary pathways and custodial mental health care.