Organic psychosis without anemia or spinal cord symptoms in patients with vitamin B12 deficiency.

The authors describe two patients with organic psychosis who had vitamin B12 deficiency and no hematologic or spinal cord abnormalities. They review the literature that supports a causal relationship between B12 deficiency and cerebral dysfunction, as measured by the EEG, and consequent organic mental changes. The authors cite evidence that these EEG and organic mental changes are reversible with B12 replacement. They emphasize that psychiatric manifestations may be the first symptoms of vitamin B12 deficiency and thus antedate anemia and spinal cord disease. They recommend consideration of B12 deficiency and serum B12 determinations in all patients with organic mental symptoms.