Risk factors for self-harm in prison: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 32711709 · doi:10.1016/S2215-0366(20)30190-5
What was done
Authors searched four electronic databases (PubMed, Embase, Web of Science, and PsycINFO) through October 31, 2019, for observational studies evaluating risk factors for self-harm in adult general prison populations compared to prisoners without self-harm. Studies using qualitative or ecological designs, lifetime-only measures, or selected non-general prison samples were excluded. Effect sizes were pooled as odds ratios (OR) using random-effects models for 40 risk factors present in at least three distinct samples. Study quality was evaluated using the Newcastle-Ottawa Scale.
What was found
Thirty-five independent studies across 20 countries were included, covering 663,735 prisoners (24,978 [3.8%] self-harmed in prison). The strongest associations with in-prison self-harm were: - Current or recent suicidal ideation: OR 13.8 (95% CI 8.6–22.1; I² = 49%) - Major depression: OR 9.3 (95% CI 2.9–29.5; I² = 91%) - Borderline personality disorder: OR 9.2 (95% CI 3.7–22.5; I² = 81%) - Lifetime history of suicidal ideation: OR 8.9 (95% CI 6.1–13.0; I² = 56%) - Any current psychiatric diagnosis: OR 8.1 (95% CI 7.0–9.4; I² = 0%) - Previous self-harm: OR 6.6 (95% CI 5.3–8.3; I² = 55%) - Solitary confinement: OR 5.6 (95% CI 2.7–11.6; I² = 98%) - Disciplinary infractions: OR 3.5 (95% CI 1.2–9.7; I² = 99%) - Physical or sexual victimisation in prison: OR 3.2 (95% CI 2.1–4.8; I² = 44%) Sociodemographic factors (OR 1.5–2.5) and criminological factors (OR 1.8–2.3) were only modestly associated.
Why it matters
This review quantifies that clinical psychiatric factors and custodial environment conditions (e.g., solitary confinement and victimization) are substantially stronger predictors of in-prison self-harm than static sociodemographic or criminal justice variables.
Limits
All included studies were observational, preventing causal inference. Marked statistical heterogeneity was present for several critical risk factors, including solitary confinement (I² = 98%), disciplinary infractions (I² = 99%), and major depression (I² = 91%). Institutional environments and definitions of self-harm varied across 20 countries.
Cited by
- supports Solitary confinement in prisoners produces substantial negative impacts on mental health and impairs their sense of self.