This chapter reviews available data in relation to the characteristics and frequency of specific psychiatric syndromes in primary endocrine disturbances. Hypocalcaemia is considered to be the fundamental cause of the psychological symptoms. In asymptomatic patients with calcium levels at the lower limit of normal (partial parathyroid insufficiency), anxiety, depression and related symptoms may be episodic, precipitated by calcium deprivation. A double-blind trial of calcium vs. placebo in these patients was effective in reducing symptomatology. Hyperprolactinaemia is a frequent disturbance in clinical endocrinology, mostly due to prolactinomas in women. Psychiatric presentations in Cushing's syndrome are well substantiated. Depression has been documented in most studies, and clinical experience suggests that its assessment may be critical. Acromegaly, the disease due to overproduction of pituitary growth hormone, has been associated with psychiatric manifestations, but the existing documentation is limited and recent studies suggest lower rates of psychiatric morbidity.