Attention-deficit hyperactivity disorder in adults with epilepsy: An indirect relationship with suicide risk

Purpose: Studies on attention-deficit hyperactivity disorder (ADHD) are scarce in adults with epilepsy. This study aimed to investigate the risk factors for ADHD and determine whether ADHD is directly associated with the risk of suicide in adults with epilepsy. Methods: ADHD was assessed using the Structured Clinical Interview for the DSM-5 Disorders Clinical Version. The Mini International Neuropsychiatric Interview (MINI) Plus 5.0.0, Neurological Disorders Depression Inventory for Epilepsy (NDDIE), and Generalized Anxiety Disorder-7 (GAD-7) were also used. Suicide risk was defined as a MINI suicidality score of >= 1. Stepwise logistic regression and mediation analyses were conducted. Results: Of the 157 adults with epilepsy, 19 (12.1 %) were diagnosed with ADHD, including inattentive (5.7 %), hyperactive (3.8 %), and combined (2.5 %) types. Thirty-two subjects (20.4 %) had a risk of suicide. ADHD was insignificantly associated with any epilepsy-related factors. The diagnosis of ADHD was not associated with suicide risk independent of NDDIE >= 14 and GAD-7 >= 7. Mediation effects of ADHD on suicidality using NDDIE >= 14 (odds ratio [OR] 2.850, 95 % confidence interval [CI] 1.398-5.811, p = 0.004) or GAD-7 >= 7 (OR 3.240, 95 % CI 1.537-6.828, p = 0.002) were statistically significant, with the proportion mediated being 84.5 % or 92.0 % of the total ADHD effect, respectively. These models were adjusted for age, sex, and composite epilepsy severity scores. Conclusions: ADHD was diagnosed in 12.1% of adults with epilepsy and was not associated with any epilepsyrelated factors. ADHD was indirectly associated with the risk of suicide resulting from depression and anxiety in adults with epilepsy.