Primary hypothyroidism: a case for vigilance in the psychological treatment of depression.

Primary hypothyroidism is a relatively common endocrine disorder that develops insidiously and can mimic depression. Between 8 and 14 per cent of patients diagnosed as depressed may have some degree of hypothyroidism. It is recommended that clinical psychologists equip themselves with sufficient knowledge to recognize the disorder. Primary hypothyroidism is described with respect to its causes, course, investigation and treatment. Suggestions are made to help psychologists determine whether a medical referral is appropriate.