Psychiatric and cognitive aspects of hypothyroidism

Abstract Diffuse and initial changes of behaviour, mood and cognition in hypothyroidism represent diagnostic and therapeutic challenges. We present four cases and discuss relevant literature. Patients were followed from time of diagnosis through the first 6-12 months of thyroxine treatment. Symptoms were identified using interviews, questionnaires and tests. The patients had reduced quality of life, depression, anxiety and impaired short time memory. All symptoms improved with thyroxine treatment, although patients did not necessarily reach premorbid functioning in 6-12 months. In the literature, depression in hypothyroidism is hypothesised to be at least partly caused by relative hypothyroidism in the central nervous system, and local brain triiodothyronine deficiency may be a possible explanation for affective and cognitive symptoms in subclinical hypothyroidism. Physicians should actively address psychiatric and cognitive aspects of hypothyroidism and in addition to thyroxine offer supportive treatment, especially to those depressed.