Psychotropic Medications in Swedish Homicide Victims and Offenders: A Forensic-Toxicological Case-Control Study of Adherence and Recreational Use

Objective: We aimed to assess the extent to which adherence to, and recreational use of, psychotropic medications influence the risk of homicide offending and victimization.

Methods: We conducted a population-based case-control study by way of linking a nationwide registry of dispensed prescriptions with a forensic-toxicological database. Homicide victims (n = 200) and offenders (n = 105) were identified for the years 2007-2009 and vehicle-accident controls (n = 1,643) for the years 2006-2013. The occurrence of congruence and incongruence between dispensed prescriptions and toxicology was used as a measure of adherence and recreational use.

Results: For antidepressants, incongruence—but not congruence—between dispensed prescriptions and toxicology was associated with a significantly increased risk of homicide offending (odds ratio adjusted for age and sex [aOR] = 6.2; 95% confidence interval [CI], 3.3-11.6) but not homicide victimization (aOR = 0.8; 95% CI, 0.3-2.0). For antipsychotics and mood stabilizers, a significantly increased risk of homicide offending was associated with incongruence between prescriptions and toxicology (aOR = 7.0; 95% CI, 2.8-17.7), whereas risk estimates for congruence were not significantly elevated for either homicide offending or victimization. For GABAergic hypnotics, congruence and incongruence were significantly associated with increased risks of both homicide offending (aOR = 5.4; 95% CI, 2.6-11.0 and aOR = 4.9; 95% CI, 2.6-9.3, respectively) and homicide victimization (aOR = 2.1; 95% CI, 1.1-4.2 and aOR = 3.2; 95% CI, 1.7-6.1, respectively). Sensitivity analyses with a subset of controls yielded similar estimates.

Conclusions: Nonadherence to medications used to treat affective and psychotic disorders appears to elevate the risk of homicide offending. Both medicinal and recreational use of GABAergic hypnotics appears to elevate the risk of homicide offending and victimization. In summary, vigilance regarding adherence to medications prescribed for mood disorders and psychosis, as well as restrictiveness regarding licit and illicit access to addictive hypnotics, might contribute to a reduction of homicidal violence.