The neuropsychiatry of vitamin B12 deficiency in elderly patients.

Vitamin B12 deficiency is a common cause of neuropsychiatric symptoms in elderly persons. Malabsorption accounts for the majority of cases. Vitamin B12 deficiency has been associated with neurologic, cognitive, psychotic, and mood symptoms, as well as treatment-resistance. Clinician awareness should be raised to accurately diagnose and treat early deficiencies to prevent irreversible structural brain damage, because current practice can be ineffective at identifying cases leading to neuropsychiatric sequelae. This clinical review focuses on important aspects of the recognition and treatment of vitamin B12 deficiency and neuropsychiatric manifestations of this preventable illness in elderly patients.