We present the case of a psychotic patient with a previous diagnosis of pellagra, admitted to an acute care unit of Miguel Bombarda Hospital, Lisbon. Pellagra is a systemic disease caused by niacin deficit; its clinical presentation is revised, taking into account psychiatric disease.

We will focus the following items:

1. - definition of pellagra and description of its main clinical symptoms

2. - historical issues of psychiatric symptoms of pellagra

3. - pellagra psychosis – evolution of classifications

4. - neuropsychiatric features of pellagra

5. - diagnosis, treatment and outcome of psychiatric illness of pellagra

Medline Research. Bibliography revision.

Clinical presentation of pellagra includes gastrointestinal, dermatological and neuropsychiatric symptoms.

The first description of pellagra dates back to 1863. In the beginning of the 20th century, approximately 30% of admissions in psychiatry were due to this disorder, which was included in the first classification of mental illness of the American Psychiatric Association.

Pellagra psychosis should be diagnosed in a patient with typical symptoms and signs of pellagra and psychotic symptoms which respond to treatment with niacin.

Pellagra is currently a rare disorder, but the diagnosis should be taken into account in alcoholic patients, undernourished, with anorexia nervosa or tuberculosis treated with isonyazid.

With proper treatment, there is a complete recovery.