Associations between selective serotonin reuptake inhibitors and violent crime in adolescents, young, and older adults – a Swedish register-based study

This study identified individuals ever dispensed a selective serotonin reuptake inhibitor (SSRI) aged 15–60 years during 2006–2013, using Swedish national registers. The outcome was violent crime conviction. The main statistical analyses assessed risks of violent crime during periods on compared to off SSRI treatment within individuals. Further analyses investigated risk over time in relation to treatment initiation and discontinuation. The study identified 785,337 individuals (64.2% female), experiencing 32,203 violent crimes in 5,707,293 person-years. Between-individual analyses found statistically significantly elevated Hazard Ratios (HRs) overall (HR = 1.10), and in 15–24 and 25–34 year-olds (HR = 1.19 and 1.16), but non-significant HRs in 35–44 and 45–60-year-olds (HR = 1.02 and 1.04). In within-individual analyses, where 2.6% of SSRI users were informative, hazards were elevated overall (HR = 1.26, 95% CI = 1.19, 1.34), and across age groups (HR of 1.35 [95% CI = 1.19, 1.54] in 25–34-year-olds to 1.15 [95% CI = 0.99, 1.33] in 35–44-year-olds). In the overall cohort, the within-individual HRs were significantly elevated throughout treatment (HRs of 1.24 to 1.35) and for up to 12 weeks post-discontinuation (HRs of 1.37 and 1.20). While questions on causality remain, these results indicate that there may be an increased risk of violent crime during SSRI treatment in a small group of individuals. It may persist throughout medicated periods, across age groups, and after treatment discontinuation. Further confirmation is needed from studies with different designs, and clinical focus should be on high-risk individuals, as a majority of SSRI-users (around 97% in our cohort) will not commit violent crimes.