Psychiatric and neurological morbidity predicts sexual offending: A nationwide, population-based, case-control study

We examined if psychiatric and neurological disorders and conditions predict sexual offending onset in a population-based, linked-registry nested case-control study of all males in Sweden suspected or convicted of a sexual (N = 48,951) or non-sexual violent offence (N = 358,653) from 1973 to 2013 and matched (1:5) to non offending Swedish general population males (241,829 and 1,786,317, respectively). We included presence of any principal or comorbid psychiatric and neurological disorders and conditions diagnosed before offending onset as predictors: any psychiatric disorder, any severe psychiatric disorder (any affective, psychotic, or personality disorder), substance use-related disorder, any self-harm or suicide attempt, and any neurological disorder (concussion, epilepsy, or traumatic brain injury). Individual disorders and conditions were bivariately associated with offending (Odds Ratios [ORs] 2.00 to 2.42 for sexual; 2.09 to 2.39 for non-sexual violent offending). Affective disorder (adjusted OR [AOR] = 0.92), concussion (AOR = 1.43), and traumatic brain injury (AOR = 1.96) independently and significantly predicted sexual offending when adjusting for other disorders and conditions. Six variables independently and significantly predicted onset of non-sexual violent offending: affective disorder (AOR = 0.92), substance use-related (AOR = 1.07) disorder, self-harm or suicide attempts (AOR = 0.89), concussion (AOR = 1.51), epilepsy (AOR = 1.11), and traumatic brain injury (AOR = 1.97). Neurological and some psychiatric disorders and conditions predicted sexual and non-sexual offending onset, suggesting that effective interventions to manage these conditions may reduce sexual and non-sexual violent offending.