Risk of common psychiatric disorders, suicidal behaviours and premature mortality following violent victimisation: A matched cohort and sibling-comparison study of 127,628 people who experienced violence in Finland and Sweden

Abstract

Background Associations between violent victimisation and psychiatric disorders are hypothesised to be bidirectional, but the role of violent victimisation in the aetiologies of psychiatric disorders and other adverse outcomes remains unclear. We aimed to estimate associations between violent victimisation and subsequent common psychiatric disorders, suicidal behaviours, and premature mortality whilst accounting for unmeasured familial confounders. Methods and Findings Using nationwide registers, we identified a total of 127,628 individuals born in Finland (1987-2004) and Sweden (1973-2004) who had experienced violent victimisation, defined as either hospital admissions or secondary care outpatient visits for assault-related injuries. These were age- and sex-matched with up to 10 individuals in the general population (n=1,276,215) and their unaffected siblings (n=132,408). Outcomes included depression, anxiety, personality disorders, substance use disorders, suicidal behaviours, and premature mortality. Participants were followed from the victimisation date until the date of the outcome, emigration, death, or December 31, 2020, whichever occurred first. Country-specific associations were estimated using stratified Cox regression models, which also accounted for unmeasured familial confounders via sibling comparisons. The country-specific associations were then pooled using meta-analytic models. Among 127,628 patients (69.0% men) who had experienced violent victimisation, the median age at first violent victimisation was 21 (interquartile range: 18-26) years. Absolute risks of all outcomes were larger in those who were exposed to violent victimisation compared to population controls (2.3-22.5 vs. 0.6-7.3 per 1000 person-years). In adjusted models, people who had experienced violent victimisation were between two to three times as likely as their siblings to develop any of the outcomes (adjusted hazard ratios [aHRs]: 1.7-3.0). Risks remained elevated two years post-victimisation (aHRs: 1.4-2.3). Conclusions Improving clinical assessment, management and aftercare psychosocial support could potentially reduce rates of common psychiatric disorders, suicidality and premature in individuals experiencing violent victimisation.