The effect of personality disorder symptoms on response to treatment with methylphenidate transdermal system in adults with attention-deficit/hyperactivity disorder.

OBJECTIVE: This trial was designed to prospectively explore the relationship among personality disorder (PD) symptoms, attention-deficit/hyperactivity disorder (ADHD), and treatment response in a randomized, double-blind, crossover clinical trial of methylphenidate transdermal system (MTS) and to confirm results of a prior exploratory study. METHOD: 67 adults who met the Utah and/or DSM-IV-TR criteria for ADHD were recruited with no attempt to include or exclude patients with PD. Responders were defined by a 50% improvement on the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS), the primary outcome measure. Personality disorder was diagnosed by the clinicians using the Structured Clinical Interview for DSM-IV-TR Axis II Personality Disorders Questionnaire, several self-report scales, and clinical observations. Subjects were categorized as: no PD (PD-negative), 1 PD (PD-positive), and 2 or more PDs (PD-plus). The study was conducted from February 2007 to December 2009 at the Mood Disorders Clinic at the University of Utah School of Medicine, Salt Lake City. RESULTS: 37% (n = 25) were PD-positive, and another 27% (n = 18) were PD-plus. In those with a PD, 65% (n = 28) had a cluster C diagnosis, 44% (n = 19) cluster B, and 5% (n = 12) cluster A. PD-plus subjects had significantly higher levels of oppositional defiant disorder (ODD) symptoms (P = .007) and emotional dysregulation (P = .004). 71% (15/21) of the PD-positive and PD-negative subjects were responders in the MTS arm (P < .001) as opposed to 38% (6/16) of the PD-plus subjects (P = .24). Conversely, the interaction between treatment (placebo versus MTS) and the 3 PD groups was not statistically significant (P = .46) when the total WRAADDS was used as the outcome measure. CONCLUSIONS: Personality disorder status was associated with more complex ADHD, especially high levels of emotional dysregulation and ODD symptoms. There was a significant treatment effect for PD-positive and PD-negative, but not PD-plus subjects. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00506285.