Differences in thyroid function studies in acutely manic adolescents with and without attention deficity hyperactivity disorder (ADHD).

The purpose of this study was to compare basal thyroid indices in adolescent (ages 12 to 18) bipolar patients with and without attention deficit hyperactivity disorder (ADHD). On the basis of earlier studies, the authors hypothesized that bipolar patients with comorbid ADHD would have lower serum triiodothyronine (T3) and thyroxine (T4) concentrations and higher serum thyroid stimulating hormone (TSH) concentrations compared with patients with bipolar disorder alone. Thirty adolescents who met DSM-III-R criteria for bipolar disorder and were hospitalized for the treatment of acute mania were assessed. Twenty patients (66%) had comorbid ADHD. The mean serum T4 concentration in this group was significantly lower than it was for patients with bipolar disorder alone. There were no significant differences between groups in serum T3 or TSH concentrations. Although, these data are preliminary and require further investigation, this may have important implications regarding the potential benefits of thyroid supplementation in adolescents with bipolar disorder and comorbid ADHD who do not respond to mood stabilizers alone.