Longitudinal patterns of cyclothymic temperament, hyperactivity and inattention, and their age-related associations with impairment in adult attention-deficit/hyperactivity disorder

Introduction Cyclothymic temperament (CT) is a subclinical trait related to bipolar disorder. Although CT is associated with ADHD, its progression across adulthood remains poorly understood. We investigated how CT and ADHD present throughout adulthood, and assessed their associations with occupational status, history of anxiety or depression, and life satisfaction. Methods In a longitudinal study spanning two decades and three waves of data collection, 818 adults with ADHD (aged 18–75) completed questionnaires about ADHD, psychiatric comorbidity, occupation, and life satisfaction. 408 participated in two waves, and 109 in three. Linear mixed models (LMMs) were computed with CT and ADHD symptoms as outcomes. Hierarchical generalized LMMs and linear regression models were computed, with occupational status, history of anxiety or depression, and life satisfaction as outcomes and CT score and ADHD symptoms as fixed effects and predictors. Nested models were compared. Age at inclusion, years since inclusion, sex, and bipolar disorder were employed as covariates. Results Years since inclusion were associated with lower CT (B=-0.16, p<0.001), while males reported lower current ADHD symptoms (Inattention: B=-1.54, p<0.001; Hyperactivity/Impulsivity: B=-1.58, p<0.001). Higher CT scores were independently associated with lower employment rates and higher rates of anxiety or depression. Conclusion Our findings indicate that CT is lower in older adults, while current self-reported ADHD symptoms remain stable across adulthood. CT was independently associated with occupational status and history of anxiety or depression, suggesting that CT contributes to impairment beyond the core ADHD symptoms. This underscores the importance of assessing and addressing affective symptoms in adult ADHD.