The psychiatry of pellagra: A forgotten disease?

Pellagra is a systemic disease resulting from decreased cellular niacinand clinically presenting with the diagnostic triad of dermatitis, diarrhoeaand dementia ('three Ds'). Although infrequently described in thepellagra literature, a number of neuropsychiatric symptoms other thandementia may present at any stage of the disease and affect a largeproportion of patients. These include anxiety, depression and mania, aswell as hallucinations, disturbances of thought and delusional beliefs. Anumber of personality changes have also been reported, resulting in social isolation, violence and aggression. Finally, ante litteram Parkinsonianfeatures have been identified since the earliest description of pellagra. Inaddition to the neuropsychiatric symptoms that may result from thedisease, it should also be noted that certain psychiatric conditions, such asanorexia nervosa and alcohol dependence, may be the underlying reasonfor the dietary deficiency. Cases of pellagra are not rare in developingcountries and may be on the increase in the developed world. It isimportant to consider the full neuropsychiatric spectrum of pellagra,particularly since a number of patients may present with a clinical picturewhich does not exactly match the 'classical' diagnostic triad (e.g.pellagra sine pellagra).