A Double-Blind Comparison of Naltrexone and Placebo in Adults With Attention Deficit Hyperactivity Disorder

The primary aim of this study is to assess whether naltrexone as a monotherapy is effective in treating ADHD in adults. Medications that increase dopamine are often effective treatments for ADHD. Since naltrexone is a kappa opioid receptor antagonist, it increases dopamine in the brain. The investigators predict that naltrexone as a monotherapy will be effective for ADHD symptoms in adults with ADHD. The investigators also plan to assess the effects of naltrexone on dopamine as measured by changes in serum prolactin. The investigators predict that naltrexone will increase dopamine as indexed by decreases in serum prolactin. This study will be a six-week, double-blind, placebo-controlled pilot study with adults 18-55 years of age with ADHD.