Pellagra: Case report of mental disorder induced by niacin deficiency


The 45-year-old male patient described in this case report had a classic case of pellagra. The patient was initially brought to a psychiatric hospital because of disorderly behavior. On admission the patient was unable to provide a history so he was given a provisional diagnosis of Psychosis Not Otherwise Specified. Despite having the cardinal symptoms of dermatitis, dementia and (three days after admission) diarrhea it took 20 days to confirm the diagnosis of pellagra. After initiation of appropriate treatment it took about six months for the patient to make a complete recovery.

PDF-Case report of mental disorder induced by niacin deficiency

This is a classic case of a mental disorder induced by niacin deficiency (pellagra). Diarrhea, dermatitis, and dementia are three cardinal symptoms of niacin deficiency. Other common neuropsychiatric symptoms include peripheral neuropathy, decreased muscle strength, depression, and hallucinations and delusions. Nicotinic acid is synthesized from the amino acid tryptophan, so niacin deficiency can directly influence the synthesis of respiratory enzymes and indirectly influence the synthesis of serotonin. The latter changes can cause dysfunctional neural transmission and, thus, give rise to neurological and psychiatric symptoms.

Lessons Learned

We believe there are several factors that lead to the delay in arriving at the correct diagnosis:

a) the patient’s cognitive state made it impossible to obtain an adequate history;

b) inpatient psychiatrists’ lack of sufficient training about and experience with physical causes of psychiatric symptoms;

c) limited exchange between specialty psychiatric hospitals and general medical hospitals; and

d) lack of the sophisticated laboratory equipment needed to diagnose uncommon medical disorders at psychiatric hospitals.

This case highlights several important lessons. Psychiatrists, particularly those who work in specialty psychiatric hospitals, need better training in the wide range of medical conditions that can present as neuropsychiatric disorders. They also need to remain vigilant because it is easy to overlook such patients in the course of their daily work of treating large numbers of patients with neuropsychiatric disorders that are not caused by physical illnesses. The long-standing separation of psychiatric and non-psychiatric medical services in China has several negative consequences; administrative efforts are needed to break down the barriers that limit exchange between psychiatric hospitals and general hospitals.

Leave a Reply