Using factor analytic models to examine the association between attention-deficit/hyperactivity disorder symptoms and...

The objective of the study was to examine the factor structure of attention-deficit/hyperactivity disorder (ADHD) symptoms in a representative population survey of adults and the association of these factors with health outcomes. Hierarchical and correlated factor analysis models were compared, and regression analyses with these models were used to determine the associations with psychological distress and substance use problems. A total of 1449 adults 18-65 years of age participated in a cross-sectional survey over the phone. ADHD symptom data came from an ADHD screener (10 items), and health outcomes were assessed using a questionnaire measuring psychological distress and two measures of substance use problems. The hierarchical general factor models with specific factors best represented the structure of ADHD in this representative population survey. The general factor and residual inattention factor were significantly associated with psychological distress, and the general factor was associated with substance use problems. From the correlated factor models, the inattention factor was associated with psychological distress and the hyperactivity factor was related to substance use problems. The hierarchical and correlated factor models explained similar levels of variance in outcomes. The results replicate previous studies indicating that a model of ADHD symptoms with a unitary dimension and separable dimensions of residual inattention and hyperactivity/impulsivity demonstrates a better fit than correlated factor models. The ADHD general factor was consistently significantly related to outcomes.