Personality Disorder in Adult Attention-Deficit/Hyperactivity Disorder: Attrition and Change During Long-term Treatment.

Personality disorders (PDs) are commonly found in adults with attention-deficit/hyperactivity disorder (ADHD) and are associated with increased ADHD symptoms and psychosocial impairment. To assess the impact of PDs or personality traits on retention rates in ADHD trials and whether treating ADHD affects the expression of PD, data were analyzed from 2 methylphenidate trials. Assessment of PDs and personality traits included using the Wisconsin Personality Disorders Inventory IV and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Personality Disorders. Attention-deficit/hyperactivity disorder symptoms were evaluated using the Wender-Reimherr Adult Attention Deficit Disorder Scale. Major findings were that subjects with cluster A, cluster B, passive-aggressive, or more than 1 PD showed more attrition. Subjects dropping out also had more schizoid and narcissistic traits. Attention-deficit/hyperactivity disorder symptoms (p < 0.001) and all personality traits (range, p = 0.03 to p = 0.001) improved, but there was almost no correlation between changes on these 2 measures. Conversely, of 11 Wisconsin Personality Disorders Inventory IV items that improved most, 8 resembled ADHD or oppositional defiant disorder symptoms.