The prevalence and correlates of dual diagnosis among adults in custody: A systematic review and meta-analysis.

BACKGROUND

Incarcerated individuals experience mental illness (MI), substance use disorders (SUD), and their co-occurrence - dual diagnosis - at higher rates than the general population. By systematically reviewing the literature on dual diagnosis in custody, we aimed to (1) estimate the pooled prevalence of dual diagnosis among adults in custody, and (2) identify the psychosocial, health-related, and criminal justice correlates of dual diagnosis.

METHOD

We searched CINAHL, CINCH, Embase, Medline, PsycINFO, and Web of Science for studies investigating dual diagnosis among adults in custody. We also conducted backward citation chaining of a previous systematic review of dual diagnosis in Australian prisons. We used random-effects meta-analysis to generate a pooled prevalence estimate of dual diagnosis and conducted a narrative synthesis of the identified correlates of dual diagnosis in the literature.

RESULTS

Twenty-five studies met the inclusion criteria; 20 had sufficient data for meta-analysis. The pooled prevalence estimate of dual diagnosis among adults in custody was 25.3 % [95 %CI: 18.6, 32.7]. Correlates of dual diagnosis included illicit substance use before 15 years old, living with someone who used substances before incarceration, violence victimisation, increased suicide risk, and a lifetime history of multiple convictions.

CONCLUSIONS

Our findings suggest that approximately one out of every four adults in custody have a dual diagnosis, highlighting the need for coordinated mental health and alcohol and other drug services for justice-involved individuals. It is crucial that correctional healthcare providers have the capacity and resources necessary to address the complex needs of adults with dual diagnosis in custody.