[Psychiatric manifestations as the only clinical sign of hypothyroidism. Apropos of a case].

This article intends to demonstrate, by presenting a clinical case, the importance of the thyroid examination in psychiatric practice. After a brief presentation of the evolution of the conceptions regarding the relation between thyroid insufficiency and psychiatric pathology, a clinical case is reported. This 63 years old man was admitted in a psychiatric ward because of his persecutive delusions and behavioral disorders (agitation, agressivity). Cognitive (namely memory) impairment was also present at the time of admission. The endocrine investigation has documented, in spite of the absence of any suggestive physical signs, a thyroid insufficiency. After the replacement treatment, all symptoms but the cognitive dysfunction disappeared. The patient's evolution is presented clinically, also rated on MMSE and MADRS scales, and biologically (TSH and T4 determination) for a 4 months period. The absence of any pathognomonical psychiatric finding, the possibility of the absence of other signs and symptoms (namely physical) in the hypothyroid state, the presence of potentially irreversible cognitive deterioration, as well as the inocuity and sensibility of thyroid hormones examination justify the systematic thyroid evaluation for all new psychiatric patients.