Thyroid function in depression and alcohol abuse: a retrospective study.

Admission thyroid function tests were reviewed in 115 euthyroid patients with depression (66), depression and alcohol abuse (30), or alcohol abuse (19). Estimated free thyroxine (EFT) levels ranged from 0.7 to 2.7 ng/100 ml (normal, 1.0 to 2.1). Levels above 2.1 ng/100 ml were associated with agitation and values under 1.1 with alcohol abuse. Mean EFT levels differed significantly among six diagnostic subgroups and paralleled rank order for severity of depression (none, secondary, reactive, single uncategorized, recurrent, psychotic). Alcohol abuse negatively affected EFT: there was a significant decrease of mean EFT level from nonabusers to abusers and, further, to intoxicated abusers. A positive association between EFT level and severity of depression, and a negative one with alcohol use, were significant when other variables considered were controlled. These two factors accounted from 28.2% of variability in EFT levels, with a minimal additional contribution of medication effect.