A metabolic disorder produced by a severe deficiency of vitamin B (niacin, nicotinic acid). Deficiencies of thiamine, riboflavin, and ascorbic acid may also be involved.The incidence of pellagrinous psychosis in this country has sharply declined in recent years due to the availability of enriched bread and emphasis on a balanced diet. Nevertheless it is still a problem in deprived or backward communities as well as among alcoholics, drug addicts, and aged, destitute individuals who live alone. The vitamin deficiency produces changes in the nerve and blood systems of the brain, resulting in a variety of psychological symptoms as well as gastrointestinal disturbances and skin lesions. (The word pellagra comes from pelle agra, meaning “rough skin” in Italian.) Early symptoms of pellagra include irritability, forgetfulness, restlessness, vague headaches, and general sluggishness. From 5 to 10 per cent of victims develop more severe symptoms, including confusion, delirium, Korsakoff’s syndrome, and hallucinations. Some patients become overexcited, while others become depressed and anxious, depending on their previous personality pattern.If the disease is not arrested, it may lead to extensive brain damage, producing stupor, convulsions, paralysis, and permanent mental deterioration. But if large doses of niacin and other dietary components are administered before brain damage occurs, the prognosis is positive. See BRAIN DISORDERS, BERI BERI.Dlustradve Case: PELLAGRINOUS PSYCHOSISM.G., female, white. In this patient pellagra had existed three years. From informant it was learned that patient had complained of pains, generally distributed about body, vertigo, stiffness of muscles, and general weakness.Upon admission to hospital, had typical pellagrous rash and loose bowels. Mentally confused, could give no account of trip to hospital or happenings of previous two weeks; frequently paid no heed to questions asked, but said over and over again, “I’m scared, Tm scared. What are you going to do to me Am I going to be killed I don’t like to be left by myself.” Knew in vague way that she was in hospital, but did not know its location, nor did she know the day or the month, and made no effort to fix hour of the day. Retention very defective. Counted from one to twenty in ten seconds with difficulty, and made no effort to reverse, nor would she perform simple mental calculations. Frequently remarked, “I have pellagra; I have been in bed two weeks. Oh, I don’t remember; I don’t remember.” Although patient denied hallucinations, from her behavior at times it was thought that they probably existed. At times patient appeared more clear than at others; she would show certain degree of insight into her condition, at one time stating that she knew there was something wrong with her mind, that everything seemed “strange” and unfamiliar.Patient ultimately recovered and showed well-marked amnesia for previous confused state. Certain happenings were more readily recalled; these coincided with periods of relative clearness. (Rosanoff, 1938)