Vitamin B12 concentrations in psychiatric patients.

In an attempt to evaluate the possible relationship between vitamin B12 deficiency and mental disease, the blood content of vitamin B12 was investigated in 835 consecutive psychiatric patients. Low serum vitamin B12 values were found in approximately 10% of these patients, due to latent pernicious anaemia in one case, post-gastrectomy in seven cases and small intestinal resection in one case. In the remaining 72 cases vitamin B12 deficiency was probably caused by nutritional insufficiency. After correction of the dietary defect there was a spontaneous increase in serum vitamin B12 in 75% of these patients. No specific psychiatric syndrome was connected with hypovitaminosis B12, but a preponderance of arteriosclerotic dementia suggests that low serum vitamin B12 values are secondary to mental illness leading to apathy and loss of appetite. Most cases will recover without further vitamin B12 supplements. But some patients may need treatment because of severe mental and physical disabilities.