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Mental Health and Biological Factors Associated with Lifetime Suicidal Behaviour Among Men in Prison: A Case-Control Study
32 Pages Posted: 1 Jun 2025
More...Abstract
Background: People in detention have increased risk of suicide compared to the general population, and suicide rate in prison worldwide represents a significant mental health burden. While several factors, including isolation, trauma, and psychiatric disorders have been identified as potential risk factors, very few studies have explored combined psychiatric and biological markers in incarcerated populations to better understand and prevent suicidality using a bio-psycho-social approach.
Methods: In a Canadian Federal detention center, 579 incarcerated men underwent a DSM-IV clinical interview and assessment using standardized scales for suicidality, inattention, impulsiveness, and aggressiveness. Biomarkers measuring the serum serotonin/kynurenine pathways were also analyzed. Statistical analyses including logistic regressions were used to identify which psychiatric diagnoses, test scores or biological measures were significantly associated to lifetime history of suicidal behaviours and/or self-harm.
Findings: Of the 579 male inmates, 137 (23.7%) had a lifetime history of suicidal behaviour. After adjusting for potential confounders, lifetime diagnosis of a mood disorder (OR 3.59, CI 2.16-5.98), post-traumatic stress disorder (OR 1.81, CI 1.19-2.77), borderline personality disorder (OR 5.33, CI 2.31-12.3) and impairments in self-concept (OR 1.94, CI 1.17–3.24) were significantly associated to lifetime suicidal behaviour. Substance use disorders, psychotic disorders, other personality disorders and serotonin/kynurenine peripheral measures were not found to be significant correlates of suicidal behaviour. Interestingly, lower kynurenine levels (p<0.001) were significantly associated with a lifetime history of mood disorders.
Interpretation: Mood disorders, post-traumatic stress disorder, borderline personality disorder, and specific ADHD-related symptoms are strongly associated with a lifetime history of suicidal behaviour in incarcerated males. Our findings also suggest that reduced levels of kynurenine, a marker of inflammation, may be linked to mood disorders in this population. These results underscore the urgent need for targeted mental health interventions in prisons to mitigate psychiatric morbidity and reduce the incidence of suicide in detention settings.
Keywords: prisoners, suicide, prison, depression, ADHD, PTSD, biomarkers, kynurenine, tryptophan, serotonin, prevention
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