Vitamin B12 deficiency: an important reversible co-morbidity in neuropsychiatric manifestations

Vitamin B12 deficiency is a common condition causing neurologic, cognitive, psychiatric, and mood symptoms. With varied religious, ethnic, and socioeconomic heterogeneity among the people in India greatly influencing their dietary habits and with the high prevalence of Helicobacter pylori infection, Vitamin B12 deficiency is not uncommon, but is often under recognized due to the lack of classical symptomatic presentation.

Retrospective study on Vitamin B12 deficiency with neuropsychiatric symptoms in patients who attended neurology, psychiatry, and geriatric OPDs for a period of 1 year in a specialized neuropsychiatric institute in South India.

Out of 259 patients who had Vitamin B12 deficiency (<220 pmol/L), 60 had neuropsychiatric symptoms. Among them the Vitamin B12 levels were <150 (severe), 150-200 (moderate), and 201-220 pmol/L (mild) in 19, 24, 17 patients, respectively. Twenty one were diagnosed with Posterior dementias, 20 with frontotemporal dementia, 7 with Schizophrenia, 4 each with Parkinson's disease and alcohol-dependent syndromes (ADS), 3 with bipolar affective disorder, and 1 with Creutzfeldt-Jakob disease. Eight patients also had hypothyroidism. First symptom of presentation was behavioral disturbances in 30 (50%), memory loss in 20 (33.9%), and sensorimotor and movement disorders in 9 (15.3%), and 56.7% were vegetarians while 43.3% were nonvegetarians. In our study, Vitamin B12 deficiency was more prevalent in elderly males (56.67%) and was associated with increased severity of behavioral disturbances (P = 0.043) which was the most common presentation. Memory loss was present in 16 (84.2%) patients of severe Vitamin B12 deficiency. Hindi mental status examination (HMSE) score was graded as <20, 20-24, 24-31 in 37 (61.7%), 10 (16.7%), and 13 (21.7%) patients, respectively. Cognitive decline in Vitamin B12 deficiency was significantly associated with increased serum cholesterol (P = 0.019) and was significantly prevalent in neurological disorders when compared with primary psychiatric illnesses (P = 0.001). Mean folate and mean homocysteine in our study was 11.7 ± 6.44 ng/ml and 17.77 ± 5.45 μmol/L, respectively. Eighty percent of the population had normal folate levels whereas mean homocysteine values were much higher than that of the western population (10-12 μmol/L).

Vitamin B12 deficiency though common in India is often overlooked. It increases the load of cognitive decline and accentuates vascular risk factors in neuropsychiatric illnesses. Vitamin B12 deficiency also increases homocysteine levels contributing to the vascular comorbidity in cerebro and cardiovascular illnesses. So prevention, early detection, and management of this reversible Vitamin B12 deficiency state is of profound importance.