Shedding Light on "the Hole": A Systematic Review and Meta-Analysis on Adverse Psychological Effects and Mortality Following Solitary Confinement in Correctional Settings.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of non-randomized observational studies
PubMed 32973582 · doi:10.3389/fpsyt.2020.00840
What was done
A systematic review and random-effects meta-analysis were conducted across PubMed, PsycINFO, Web of Science, and Google Scholar to evaluate psychological effects and mortality associated with solitary confinement in correctional facilities. Eligible studies used operational definitions for solitary confinement and compared exposed inmates to non-exposed controls. Thirteen studies were included (total N = 382,440 inmates; 23% exposed to solitary confinement). Five studies (n = 4,517) were meta-analyzed for psychological symptom scales using standardized mean differences (SMD), and two studies (n = 243,050) were meta-analyzed for mortality odds ratios.
What was found
Solitary confinement was associated with an increase in adverse psychological effects, self-harm, and mortality, particularly suicide. Meta-analysis of 5 studies showed an SMD of 0.45 for general psychological symptomatology, which increased to 0.51 after outlier exclusion. Small-to-moderate significant effects were observed for mood, psychotic, and hostility symptoms. Meta-analysis of 2 studies showed a trend toward a moderate effect for all-cause and unnatural mortality (suicide, homicide, overdose, and accidents). The abstract does not provide exact numerical effect sizes or confidence intervals for mortality.
Why it matters
This review aggregates quantitative evidence showing that adverse psychological deterioration and elevated mortality risk in solitary confinement persist beyond the baseline impact of general incarceration or pre-existing psychiatric illness.
Limits
All included studies were observational or case-control designs, carrying an inherent risk of confounding by indication (e.g., inmates with pre-existing behavioral dysregulation or severe illness being selectively placed in solitary confinement). Only 5 of 13 studies were meta-analyzable for psychological symptoms and only 2 for mortality. Post-release death risk remains understudied, and exact point estimates and confidence intervals for mortality outcomes were omitted from the abstract.
Cited by
- supports Solitary confinement in prisoners produces substantial negative impacts on mental health and impairs their sense of self.