Risk of Injury According to Attention Deficit Hyperactivity Disorder, Comorbid Mental Illness, and Medication Therapy.

INTRODUCTION We identify the risk of selected types of injuries among patients with ADHD or ADHD and comorbid mental illness. We also assess whether selected medications used by patients with ADHD increase the risk of comorbid mental illness or influence the association between ADHD and injury. METHODS A retrospective cohort study design was conducted using medical claims data from the Deseret Mutual Benefit Administrators (DMBA). ADHD diagnosis, injury, medication, and demographic data were extracted from claims files during 2001-2013. Rate ratios were adjusted for age, sex, and calendar year. RESULTS Patients with ADHD were 7.9 (95% CI 7.6-8.2) times more likely to have psychosis, 5.5 (3.9-7.8) times more likely to have alcohol- or drug-induced psychosis, and 6.0 (5.9-6.2) times more likely to have neurotic or personality disorder. Therapy with amphetamine was positively associated with neurotic or personality disorder (rate ratio=1.08, 1.02-1.15); methylphenidate was negatively associated with neurotic or personality disorder (0.90, 0.84-0.97); and atomoxetine was positively associated with psychosis (1.33, 1.21-1.46), alcohol- or drug-induced psychosis (2.38, 1.04-5.43), and neurotic or personality disorder (2.38, 1.04-5.43). ADHD was associated with an increased risk of injury, with ADHD and comorbid mental illness having a stronger increased risk of injury. Psychostimulants ameliorated the increased risk of injury for patients with ADHD. CONCLUSION Patients with ADHD have an increased risk of injury, significantly more so for those with ADHD and comorbid mental illness. Psychostimulants can lower the risk of injury among patients with ADHD.