Testing homocysteine-induced neurotransmitter deficiency, and depression of mood hypothesis in clinical practice

Abstract

Background: High total plasma homocysteine (tHcy) levels may cause neurotransmitter deficiency, and consequently depression of mood. We have recently shown that mixed oral nutritional supplements containing B-group vitamins led to a statistically significant benefit on depressive symptoms. The aim of this report was to examine the association between elevated plasma tHcy and symptoms of depression in older patients. Methods: two-hundred and thirty-six hospitalised acutely ill older patients, who were part of a randomised double-blind placebocontrolled trial, were assigned to receive daily mixed oral nutritional supplements containing B-group vitamins or a placebo for 6 weeks. Outcome measures included symptoms of depression measured using Geriatric Depression score and plasma tHcy levels. Results: the mean tHcy concentration fell by 22% among patients given the supplements compared with the placebo group (mean difference 4.1 μmol/l (95% CI: 0.14-8.03), P = 0.043). tHcy concentrations was divided into four quartiles and analysed against depression scores. tHcy concentrations in the first relative to the fourth quartile of the distribution were associated with a lower depression symptoms at the end of the supplement period (Geriatric depression score r = -0.20, P =0.042). Conclusions: lower plasma tHcy concentrations were associated with reduced depression symptoms in older patients recovering from acute illness. © The Author 2011. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved.