B Vitamins Play Important Roles in Mental Health Care

In a previous blog post, I reviewed the evidence for folate supplementation in mental health care. Emerging research findings show that other B vitamins: B12, thiamin, and niacin, also play important roles in maintaining optimal mental health. These B vitamins are essential parts of a healthy diet and may help alleviate symptoms of alcohol abuse, depressed mood, schizophrenia, and cognitive impairment in some cases. Many findings are based on small studies inconsistent and B vitamin supplementation should not be recommended as a first-line or standalone "treatment" for these mental health problems.

B12 for cognitive impairment

Vitamin B12 is often recommended for elderly non-demented individuals who complain of impaired cognition; however, research findings are inconsistent. In a pilot study (N = 22), 18 elderly patients with abnormal low serum B12 levels and cognitive impairment were treated with B12 (1 mg per day intramuscularly) for 1 week, followed by weekly 1-mg injections for 1 month, then monthly 1-mg injections for 6 months. Patients who had been cognitively impaired for less than 1 year experienced significant improvement, whereas patients who had been impaired for longer than 1 year became worse, suggesting that supplementation may ameliorate symptoms related to B12 deficiency only in the early stages of cognitive impairment.

B vitamins for alcohol abuse, depressed mood, and dementia

Chronic alcoholics are often deficient in thiamin, folate, B6, and B12 because of the toxic effects of alcohol on the mucosal lining of the stomach and small intestine which interferes with normal absorption. Animal studies suggest that low serum thiamin levels are associated with increased alcohol craving. Niacin in the form of 1.25 g per day of nicotinamide taken with a meal before drinking may protect the liver against the acute toxic effects of alcohol in individuals who have relapsed. Thiamin is essential for the metabolism of the neurotransmitter acetylcholine and its release from presynaptic neurons. Depressed patients report improved mood and energy with daily thiamin supplementation of 50 mg. When taken together with conventional antipsychotic medication, 500 mg thrice daily of thiamin (vitamin B1) may lessen the severity of psychotic symptoms in patients with chronic schizophrenia. Thiamin-dependent enzymes may be abnormal in Alzheimer's disease. Findings on high-dose thiamin (3 to 8 g per day) in Alzheimer's disease are inconsistent.

Niacin for schizophrenia

A few early double-blind placebo-controlled studies reported that large doses of niacin (up to 3 to 8 g per day) reduced symptom severity in individuals diagnosed with schizophrenia. A combined regimen of high-dose niacin and an antipsychotic medication reportedly resulted in relatively greater improvement in positive symptoms of hallucinations and delusional thinking compared to patients treated with antipsychotics alone. A subsequent review of 53 trials on niacin and other vitamins in the treatment of schizophrenia and other severe chronic psychiatric disorders identified methodological flaws in early studies and concluded that findings reached only marginal statistical significance. Despite the absence of strong evidence, high-dose niacin is a standard therapy for schizophrenia in orthomolecular psychiatry, and case reports of dramatic outcomes continue to be published in the medical literature. A retrospective analysis of negative findings of controlled trials suggested that non-medicated patients with schizophrenia in the early acute phase of illness may experience significant and sustained benefits from high doses of niacin, in contrast to medicated patients with schizophrenia or individuals in the chronic phase of the illness.

Safety issues

Serum B12 levels should be routinely checked before recommending folate supplementation. Folic acid interferes with phenytoin metabolism, lowering serum levels and placing individuals with seizure disorders at increased risk.