Treatment of cocaine dependent treatment seekers with adult ADHD: double-blind comparison of methylphenidate and placebo

Abstract

The purpose of this double-blind 14-week trial was to compare the efficacy of sustained-release methylphenidate (MPH) to placebo (PBO) in treating adult attention deficit hyperactivity disorder (ADHD) symptoms in current cocaine dependent (CD) treatment seekers. The randomized sample consisted of 106 participants who were predominately male (83%) and 60% Caucasian, 14% Hispanic, 20% African-American and 6% other. All participants met DSM-IV criteria for ADHD and CD. There were no significant demographic differences between the two treatment groups. All participants received weekly individual cognitive behavioral therapy. There was no difference in retention rate based on treatment group (p=.91). The majority of the PBO group and the MPH group reported >30% improvement in their ADHD symptoms (55% versus 47%), with no significant difference between the two groups (p=.44). Using a combined outcome measure (>30% reduction in ADHD symptoms and CGI <3), the response rates were similar for both groups (28% PBO versus 30% MPH; p=.83). Longitudinal analyses of the urine toxicology data using generalized estimating equations, revealed a decrease in the probability of cocaine positive urine samples during the trial for the MPH group compared to the PBO group (p=.001). Further analysis suggested that for the MPH group, ADHD treatment responders, based on a semi structured clinical interview, were more likely to have a reduction in cocaine use compared to the non-ADHD responders. Although sustained-release MPH did not show superiority over PBO in treating ADHD symptoms, this trial provides some evidence that improvement in ADHD symptoms (clinician rated) among those patients receiving MPH, but not placebo, was associated with a reduction in cocaine use.