Examining the validity of the ADHD concept in adults and older adults

It is crucial to clarify the structure of attention-deficit/hyperactivity disorder (ADHD) symptomatology in all age groups to determine how to best conceptualize this disorder across the lifespan. We tested the ADHD factor structure across adulthood and investigated independent associations with executive functions.

Data from 645 adults aged 18-59 and 233 adults aged 60-85 were drawn from the Nathan Kline Institute Rockland Sample. Participants completed the Conners Adult ADHD Rating Scale and tests of executive functioning. Invariance of the ADHD factor structure was investigated using confirmatory factor analyses. Associations with cognition were explored using multiple linear regression.

Results confirmed a bifactor model with 3 specific factors (inattention, hyperactivity, and impulsivity). Factor loadings and item intercepts were invariant across ages. Levels of hyperactivity and impulsivity were lower in older adults. Inattentive symptoms in young adults were positively related to cognitive flexibility. In older adults, ADHD symptoms predicted poorer working memory.

ADHD symptoms manifest similarly across adulthood. The lack of robust associations between ADHD symptomatology and executive functions raises concerns about the usefulness of neuropsychological measures in diagnosing adult ADHD. These results support the validity of the ADHD concept in older adults but suggest a need for age-appropriate normative criteria.