Lachner C, Martin C, John D, Nekkalapu S, Sasan A, Steinle N, Regenold WT: Older adult psychiatric inpatients with non-cognitive disorders should be screened for vitamin B12 deficiency. J Nutrition, Health and Aging,  2013. Advance online publication. doi: 10.1007/s12603-013-0378-z.

Up to 50% of people with B12 deficiency have incident neuropsychiatric symptoms which often precede hematological manifestations. The clinical concern is that, by the time B12 level declines into the abnormal range, it is likely that the pathophysiologic changes underlying neuropsychiatric symptoms have already begun.

It is clinically justified to screen acute older adult psychiatric inpatients for B12 deficiency whether or not cognitive symptoms are present given the highly prevalent and easily treatable possible and probable B12 deficiencies in this population.  The presence of gastric disease or a high MCV should warn for possible deficiencies in these patients.

While the American Psychiatric Association (APA) Practice Guidelines on Alzheimer’s Disease include screening for B12 deficiency, our review of the current APA guidelines for the psychiatric evaluation of adults with, bipolar disorder, delirium, major depressive disorder and schizophrenia, make no mention of screening serum B12 levels, except when evaluating cognitive symptoms in the context of depression.  A growing body of literature has demonstrated an association of B12 deficiency with not only cognitive impairment, but also mood and psychotic symptoms. Treatment outcomes have also been associated with Cobalamin status.