Increased serum thyroid hormone binding in narcotic addicts is due to liver disease.

The cause of increased thyroid hormone binding in narcotic addicts has been investigated. The average T3, T4, and T3 binding ratio were all significantly higher in addicts than in controls. Free T4 and free T3 indices were normal. Those patients who had abnormally high T3 binding ratios had significantly more severe abnormalities of liver function than the other methadone-treated addicts. Together with evidence that chronic active hepatitis in the nonaddicted population is associated with increased serum thyroid hormone binding, these observations lead us to conclude that the increased serum thyroid hormone binding and total thyroid hormone concentration found in sera of narcotic addicts is due to associated liver disease.