The British Journal of Psychiatry
A Survey of Vitamin B12 Deficiency in an Elderly Psychiatric Population


A survey of vitamin B12 deficiency was carried out in 117 psychiatric patients. 8.5 per cent. of all the patients and 12 per cent. of new admissions had serum vitamin B12 levels less than 150 µµg. per cent. A comparison with serum B12, levels in 100 elderly medical patients showed no evidence of a decline in the serum B12 level with age in either group of patients.

Before hospital admission most of the patients had been taking inadequate diets. Poor nutrition was evident in all categories of patients, functional as well as organic. Serum folate activity levels were measured in 59 patients, and subnormal values (<5.9 mµg./ml.) found in 82 per cent. of new admissions.

Difficulties in the differential diagnosis of nutritional folate deficiency and pernicious anaemia have been described. Of the 10 patients with serum B12 levels less than 150 µµg. per cent., 5 had pernicious anaemia and 4 had nutritional deficiency states. In one patient the cause of a low serum B12 level was not established. Caution is necessary in the interpretation of low serum B12 levels unless the nutritional status of the patient is also known. Some causes of low serum B12 levels in psychiatric patients have been reviewed and the importance of nutritional deficiency states emphasized.

The value of a simple screening test for vitamin B12 deficiency was examined by correlating serum vitamin B12 results with haematological abnormalities based upon an examination of the peripheral blood film and an estimation of the haemoglobin level. Haematological abnormalities, consisting of morphological changes in the red cells or anaemia, were present in 9 of the 10 patients with serum B12 levels less than 150 µµg. per cent., in all 5 patients with serum B12 levels less than 100 µµg. per cent., and in all the patients with pernicious anaemia. Hypersegmentation of the neutrophils when present as the only haematological abnormality did not correlate with low serum B12 levels.

Few psychiatric hospitals are equipped for carrying out large numbers of vitamin B12 assays. The results of this survey suggest that a preliminary screening of all patients by a haemoglobin estimation and careful blood film examination is a useful and practical procedure in selecting patients for further investigation. In an acute psychiatric unit this may involve selective vitamin B12 assays in as many as 35 per cent. of new admissions. Whether the time and expenditure involved in this can be justified depends largely upon the clinical significance to be attached to low serum B12 levels in psychiatric patients.