Dr Adrian Lopresti from the School of Psychology and Exercise Science studied the effects of curcumin, the medicinal compound which gives turmeric its distinctive yellow colour, in a randomised, double blind, placebo-controlled study of 56 volunteers with a major depressive disorder. Half were treated with a patented curcumin extract (500mg twice daily) and the other half took a placebo for eight weeks.
From weeks four to eight of the study, Dr Lopresti found that curcumin was significantly more effective than the placebo in improving several mood-related symptoms in the volunteers. The compound had an even greater efficacy in a small subgroup of individuals with atypical depression, which can be characterised by significant weight gain or increased appetite and hypersomnia.
"In animal-based studies curcumin has been consistently shown to have antidepressant effects and it has been hypothesised that curcumin would have antidepressant effects in people with major depression," said Dr Lopresti, who is a clinical psychologist in a private practice.
"There have been a few positive human-based studies investigating the effects of curcumin in depression. However, this is the first randomised, double blind, placebo-controlled study and over the longest duration."
Dr Lopresti said previous studies had found strong links between inflammation in the body and depression and that curcumin influenced several biological mechanisms including inflammation.
"The findings from this study suggest that depression can be treated with an agent that has anti-inflammatory and antioxidant properties," he added.
"Our findings support consistent research that depression is associated with increased inflammation. Despite what has been previously believed, depression is not all about brain chemicals such as serotonin.
"This could be why there were particularly good results in the subgroup of volunteers with atypical depression because this condition is often associated with higher levels of inflammatory proteins."
Dr Lopresti said he hoped to replicate the study with a larger group of participants and over a longer period of time to provide a more robust evaluation of the clinical effectiveness of curcumin.
"It would be useful to investigate whether a higher dose of curcumin will have a greater and more rapid antidepressant effect," he said.
"But although curcumin has several potential health benefits, I would not recommend it as a first line of treatment for depression yet. More research is required."
More information: "Curcumin for the treatment of major depression: A randomised, double-blind, placebo controlled study," Journal of Affective Disorders Volume 167, Pages 368–375, October 1, 2014 DOI: 10.1016/j.jad.2014.06.001