Assessment, Ahead of Print.
Previous studies examining the factor structure of attention-deficit/hyperactivity disorder (ADHD) symptoms in adults using self-report measures have shown mixed results, supporting two-, three-, and bifactor solutions. The current study further investigated the structure of ADHD symptoms in adults using the Current Symptoms Scale and rigorous model evaluation in a sample of 892 college students. Confirmatory factor analysis was used to analyze and compare five-factor structures; a single-factor model, a two-factor model, a three-factor model, and two bifactor models. A single-factor model with correlated residuals best fit the data. Factor correlations with nearly all related constructs (i.e., symptoms of oppositional defiant disorder, depression, impairment, previous ADHD diagnosis, grades, and substance use) were significant in the expected directions and the model was invariant across gender. These findings contribute to a growing body of work suggesting a unidimensional factor may best represent ADHD symptoms in adults. Implications are discussed.