Associations between antipsychotics and risk of violent crimes and suicidal behaviour in personality disorder

Background Despite uncertain benefits, people with personality disorder are commonly treated with antipsychotic medication. Objective To investigate the association between antipsychotics and violent crimes and suicidal behaviour in individuals with personality disorder. Methods We used nationwide Danish registries to identify all individuals with diagnosed personality disorder aged 18-64 years during 2007 to 2016. Antipsychotics were recorded in dispensed prescriptions, and individuals were followed up for police-recorded suspicions for violent crimes and healthcare presentations of suicidal behaviour. We applied a within-individual design where outcome rates for individuals with personality disorder during medicated periods were compared with rates during non-medicated periods. Findings The cohort included 166 328 people with diagnosed personality disorder, of whom 79 253 were prescribed antipsychotics, presented at least one outcome and were thus included in the within-individual analyses. Compared with periods when individuals were not on antipsychotic medication, violent crime suspicions were 40% lower (incident rate ratio (IRR) 0.60, 95% CI 0.55 to 0.63) in men and 10% lower (IRR 0.90, 95% CI 0.79 to 1.01) in women, while rates of suicidal behaviour were 32% lower both in men (IRR 0.68, 95% CI 0.66 to 0.71) and in women (IRR 0.68, 95% CI 0.65 to 0.70). In subgroup analyses, the magnitude of the association varied across specific personality disorders for criminal outcomes but less for suicidal behaviour, with largest association in dissocial personality disorder for violent criminality (IRR 0.53, 95% CI 0.47 to 0.59). Conclusions Treatment with antipsychotics was associated with reduced risks for violent crime suspicions and suicidal behaviour among individuals with personality disorder. Clinical implications Potential effects of antipsychotics on suicidal behaviour and violence should be taken into account when considering treatment options for people with personality disorders.