Routine thyroid function studies in a community referred sample of boys with ADHD were examined for evidence of generalized resistance to thyroid hormone at the National Institute of Mental Health, Bethesda, MD. TSH, T3, and T4 values in 53 subjects were not in the range suggestive of global or pituitary thyroid hormone resistance, and variability of values was not greater in ADHD subjects compared to 41 normal controls. Motor activity measured by an actometer was increased as T4 values increased (P=.06). 
COMMENT. The authors conclude that a generalized resistance to thyroid hormone (GRTH) is rare, and thyroid function should not be measured routinely in nonfamilial ADHD. Another recent study from the National Institutes of Health, by endocrinologists, had shown that 70% of children with GRTH met criteria for ADHD. (Hauser et al, 1993; see Ped Neur Briefs April 1993;7:25). Impairments of cognition, attention, and behavior may be seen with hyperthyroidism. The correlation between motor activity and serum T4 values in the above study is of interest and deserves further study, if not routine examination in ADHD.