Elevated triiodothyronine in psychopathy - possible physiological mechanisms.

We assessed a total range of peripheral thyroid hormone fractions, binding globulins, and thyroid-active antibodies in 37 medication-free, violent or sexual offenders, aged 17-45 years, to describe possible mechanisms involved in the thyroid metabolism of aggressive men. The ratio between T3 and T4 correlated with ratings of psychopathy, indicating increased peripheral deiodination as a biological covariate to callous personality traits. Autoimmune antibodies, hepatic failure, abnormal binding globulins, or substance abuse did not affect the association.