Depression pellagra

Niacin Nicotinic acid, nicotinamide Coenzyme in oxidation and reduction reactions, functional part of NAD and NADP Pellagra—photosensitive dermatitis, depressive psychosis... 

Nicotinate and nicotinamide, together referred to as niacin, are required for biosynthesis of the coenzymes nicotinamide adenine dinucleotide (NAD"") and nicotinamide adenine dinucleotide phosphate (NADP" ). These both serve in energy and nutrient metabolism as carriers of hydride ions (see pp. 32, 104). The animal organism is able to convert tryptophan into nicotinate, but only with a poor yield. Vitamin deficiency therefore only occurs when nicotinate, nicotinamide, and tryptophan are all simultaneously are lacking in the diet. It manifests in the form of skin damage (pellagra), digestive disturbances, and depression. 

Pellagra is often characterized by mental abnormalities such as anxiety, irritability, and depression. The classic symptoms of pellagra are known as the 4 Ds -dementia, diarrhea, dermatitis, and death. Inflammation of mucosal surfaces, weakness, anorexia, and other gastrointestinal disturbances are also seen. Niacin (300 to 500 mg per day) is the definitive therapy. 

Pellagra is characterized by a photosensitive dermatitis, like severe sunburn, typically with a butterfly-like pattern of distribution over the face, affecting aU parts of the skin that are exposed to sunlight. Similar skin lesions may also occur in areas not exposed to sunlight, but subject to pressure, such as the knees, elbows, wrists, and ankles. Advanced pellagra is also accompanied by a dementia or depressive psychosis, and there may be diarrhea. Untreated pellagra is fatal. 

The other characteristic feature of pellagra is the development of a depressive psychosis, superficially similar to schizophrenia and the organic psychoses, but clinically distinguishable by the sudden lucid phases that alternate with the most florid psychiatric signs. The mental symptoms may be the result of tryptophan depletion, and hence a lower availability of tryptophan for synthesis of the neurotransmitter serotonin (5-hydroxytryptophan). But the role of cADP-ribose and NAADP in controlling calcium release in response to neurotransmitters (Section 8.4.4) and impaired energy-yielding metabolism in the central nervous system as a result of depletion of NAD (P) may also be important. 

Gram doses of nicotinamide have been used in so-called orthomolecular psychiatry as a treatment for schizophrenia, originally because of the similarities between schizophrema and the depressive psychosis of pellagra. The underlying rationale for this use is that such high doses of niacin may deplete methyl donors, and at least one of the theories of the biochemical basis of schizophrenia was that the condition is caused by inappropriate methylation of neurotransmitter metabolites to yield psychotogenic compounds (Hoffer et al., 1957). There is no independent confirmation of the efficacy of nicotinamide in the treatment of schizophrenia. 

Nicotinic acid (niacin) Nicotinamide adenine dinucleotide (NAD+) Oxidation-reduction Pellagra (dermatitis, depression, diarrhea)... 

Niacin Deficiency. Niacin deficiency, manifested as pellagra, is characterized by the four Ds dermatitis, diarrhea, depression, and death. The dermatitis is characterized by a pigmented rash developing on skin exposed to... 

The earliest neurologic symptoms of pellagra are reminiscent of neurasthenia, with insomnia, fatigue, nervousness, irritability, and depression with memory loss (Victor et al, 1971). A progressive dementia can develop, but this seems unlikely to be caused solely by the absence of niacin. An acute confusional syndrome also occurs in human pellagra, and this is reversible with niacin therapy. A central neuritis is prominent in the large motor cortex cells (the Betz cells). This is not a demyelinating process like Bj2 deficiency but a primary involvement of the whole neuron. 

Niacin deficiency leads to unwanted multisystemic problems that are often associated with dermatological changes. Pellagra is a condition in which niacin deficiency causes a symmetrical pigmented rash, thickened skin and superficial scaling which are found in sun-exposed body areas. The classic triad of niacin deficiency are the three D s—dermatitis, diarrhoea and dementia (Hegyi et al. 2004). Some of the effects on the central nervous system include depression, anxiety, restlessness and poor concentration. In addition, alcoholic individuals with poor nutrition can develop pellagroid encephalopathy (Cook et al. 1998). The role of niadn deficiency in cardiovascular disease and lipid metabolism remains to be fully explored. 

Psychiatric manifestations are fairly common but are easily overlooked due to their non-specific nature. These are commonly seen as irritability, poor concentration, anxiety, fatigue, restlessness, apathy and depression. The occurrence of psychosis in pellagra is an uncommon finding, especially as an early feature and we have described it under a separate heading. Additionally, the psychotic spectrum is usually seen in advanced stages of pellagroid encephalopathy, commonly found in chronic alcoholics (Cook et al. 1998). 

The typical features of pellagra are dermatitis, particularly of areas of skin which are exposed to light or injury inflammation of mucous membranes including the entire gastrointestinal tract, which results in a red, swollen, sore tongue and mouth, diarrhea, and rectal irritation and psychic changes, such as irritability, anxiety, depression, and, in advanced cases, delirium, hallucinations, confusion, disorientation, and stupor. 

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