Relationships between thyroid indices and symptoms of anxiety in depressed outpatients.

Scores on rating scales measuring symptoms of depression, panic anxiety, state anxiety, trait anxiety, and agoraphobic avoidance were correlated, using multivariate statistics, with total thyroxine- and thyrotropin-releasing hormone concentrations in outpatients with major depression. A significant inverse relationship was demonstrated between agoraphobic avoidance and total thyroxine concentrations in female patients. No other symptom ratings were significantly associated with these thyroid indices. The depressed patients scored in the clinically significant range for agoraphobic symptoms. Assessment of agoraphobic avoidance may help identify a clinically and biologically distinct subgroup of depressed patients.