Prevalence studies show that nearly 80% of young offenders present psychiatric comorbidity. Juvenile offenders are at 3 times higher risk of being diagnosed with a psychiatric disorder. Recent systematic reviews have mainly focused on youth in detention neglecting youth in the community. Females and ethnic minorities have been overlooked in the literature in spite of the increasing rates of psychiatric disorders striking these groups.

To perform a meta-analysis on the prevalence rates of various mental disorders including depression, psychosis, PTSD, conduct disorder, ADHD, learning disabilities and personality disorders among young offenders. Self-harm and suicidal behaviour are examined too.

To compare the prevalence of psychiatric disorders among young offenders across custody and community and to emphasise on gender, age, and ethnic variations.

Relevant studies have been identified with computer-assisted searching and scanning of reference lists. Prevalence of mental disorders based on gender, age and ethnicity along with potential moderating factors are extracted from the included studies. Meta-regression is performed to test covariates that might have contributed to differences in prevalence rates across studies.

After searching the relevant literature, 99 studies were determined to be eligible for data extraction.

Young offenders with ongoing mental health problems comprise a vulnerable group within forensic psychiatric services that needs special attention. More prevalence studies should be conducted to improve mental health provision. Ethnic, gender, and age variations across young offenders should be addressed and turn interventions into a tailored process that responds to the young person's particular treatment needs.

The authors have not supplied their declaration of competing interest.