Screening for vitamin B12 deficiency in psychiatric patients

Psychiatric patients are frequently screened for vitamin B₁₂ deficiency in the absence of hematologic or other neurologic findings. To determine the yield of this practice, 162 psychiatric inpatients were screened for vitamin B₁₂ deficiency. Ten patients had initial low serum vitamin B₁₂ levels, but only two had definite B₁₂ deficiency on further evaluation. Three patients who had initially low B₁₂ levels had normal levels subsequently during outpatient follow-up. When low serum vitamin B₁₂ levels are discovered in psychiatric patients without hematologic or neurologic findings, a diagnosis of B₁₂ deficiency should not be presumed without further evaluation. Received from the Department of Medicine, New England Deaconess Hospital, and Harvard Medical School, Boston, Massachusetts.