Inattentive Symptoms of ADHD Are Related to Evening Orientation

Objective: Morningness is a stable characteristic of individuals, related to impulsivity and novelty seeking. The evening orientation is a risk factor for psychiatric conditions such as depression and personality disorders. The authors hypothesized that adults suspected of having ADHD are more evening oriented than adults without ADHD. Method: Exploratory factor analyses were performed on the polychoric correlation matrices of the full Adult Self-Report Scale for ADHD (ASRS) and the Composite Scale of Morningness (CSM). Results: As expected, two factors for the ASRS—Inattention and Impulsivity— Hyperactivity—and three factors for the CSM were retrieved. All three CSM factors correlated negatively with ASRS Inattention, none with ASRS Impulsivity—Hyperactivity. Conclusion: Inattention is more strongly related to eveningness than is Impulsivity—Hyperactivity, and therefore eveningness may constitute an endophenotype of the predominantly inattentive subtype of ADHD. These findings need to be replicated in a patient population with a standardized assessment of sleep quality.