Behavioral dysfunction in hyperthyroidism. Improvement with treatment.

We measured behavioral dysfunction in hyperthyroid patients to determine if improvement occurred with therapy. The Sickness Impact Profile (SIP), an interview designed to measure sickness-related behavior, was administered to 14 hyperthyroid patients on initial diagnosis and at intervals during treatment. All patients received medical therapy (propranolol hydrochloride, propylthiouracil, and/or radioactive iodine) and showed both biochemical improvement as measured by adjusted serum thyroxine (T4) levels and functional improvement as measured by the SIP score. Patients were less productive during the day and required naps and rest. Although they were irritable, critical, and demanding in their family and social interactions, they were not less affecionate, isolated, or less interested in others. Altered sleep and rest patterns may have been responsible for disrupting normal daily activities. Treating the underlying metabolic disorder resulted in a relatively prompt resolution of the patients' dysfunctional behavior.