Selective serotonin reuptake inhibitor (SSRI) use is modestly associated with violent crime, according to a study published this week in PLOS Medicine. The cohort study, by Seena Fazel from the University of Oxford, and colleagues, showed in subgroup analysis that this association was evident in participants aged 15-24, but not significant for individuals aged 25 and older.

SSRIs are widely prescribed, but inconclusive evidence links SSRI use with violent behavior. In this study, Fazel and colleagues compared the rate of violent crime while individuals were prescribed SSRIs with the rate of violent crime in the same individuals while not receiving medication, using matched data from the Swedish Prescribed Drug Register and the Swedish national crime register. During the 4-year study period, about 850,000 individuals (10.8% of the Swedish population) were prescribed SSRIs, and 1% of these individuals were convicted of a violent crime.

The result was an overall association between SSRI use and violent convictions (Hazard Ratio [HR] =1.19, 95% CI: 1.08-1.32, p<0.001, absolute risk=1.0%). In age-stratified analysis, associations between SSRI use and convictions for violent crimes were significant for individuals aged 15 to 24 years (HR = 1.43, 95% CI 1.19-1.73, p < 0.001, absolute risk = 3.0%) but not for older individuals (e.g., age 25-34 (HR = 1.20, 95% CI 0.95-1.52, p = 0.125, absolute risk = 1.6%)). Increased risks were also found in individuals aged 15-24 years for violent arrests, non-violent convictions and arrests, non-fatal accidental injuries and emergency contacts for alcohol problems.

These findings do not prove causation, as possible confounding by one or more unidentified factors linked to both SSRI use and violent crime may explain the results. Notably, the within-person approach used does not account for time-varying risk factors such as symptom severity.

However, if these results are confirmed, warnings about the increased risk of violent behavior among young people taking SSRIs might be needed. However, clinicians must weigh the SSRI-associated increase in violent crime against SSRI-associated reduction of disability, hospitalization, and suicide.

The authors state, “From a public health perspective, this worsening of overall morbidity and mortality might argue against restrictions on the primary care prescribing of SSRIs as long as potential risks are disclosed.”