Researchers are finding mounting evidence that an anti-inflammatory compound in a common kitchen spice might help reduce symptoms of major depressive disorder (MDD). Curcumin is the active ingredient in turmeric, the Indian spice that imparts the yellow coloring to foods like curry, butter, mustard, and cheese. It has long been a mainstay of Ayurvedic and traditional Chinese medicine as a treatment for various ailments.1
In the past 2 years, several randomized controlled trials have found support for the efficacy of curcumin in the treatment of MDD. Though it is too soon to explicitly recommend it as a treatment for depression, “curcumin does have an effect on several physiological systems that are implicated in the causes of depression,” Roger S. McIntyre, MD, a professor of psychiatry and pharmacology and head of the Mood Disorders Psychopharmacology Unit at the University of Toronto, told Psychiatry Advisor. “It certainly would be a reasonable hypothesis that it could be in possession of antidepressant properties.”
One recent study finding support for the antidepressant effects of curcumin was published in October 2014 in the Journal of Affective Disorders.2 In the randomized, double-blind, placebo-controlled trial, researchers from several universities in Australia assigned 56 patients with MDD to receive either curcumin or placebo capsules twice a day for 8 weeks. Until the fourth week, each group had similar improvements in scores on the Inventory of Depressive Symptomatology self-rated version (IDS-SR30). From the fourth week through the eighth week, however, there was a significantly greater improvement in scores in the curcumin group, especially among patients with atypical depression.
“Curcumin can influence several mechanisms in the body; in particular, it is a powerful natural anti-inflammatory and antioxidant,” study co-author Adrian Lopresti, PhD, a clinical psychologist and researcher at the School of Psychology and Exercise Science at Murdoch University, told Psychiatry Advisor. “This has relevance to depression because people with depression have greater inflammation and oxidative stress, which can affect all major organs in the body, including the brain.” Chronic inflammation can decrease levels of serotonin and dopamine and lead to degeneration in certain brain areas. It is possible that the antioxidant and anti-inflammatory effects of curcumin can restore these neurotransmitters and protect the brain, eventually leading to improvements in mood.
Before and after the 8-week treatment period, Lopresti and colleagues had also collected saliva, urine, and blood samples from participants to identify potential biomarkers associated with curcumin’s antidepressant mechanisms. They reported the results of their analysis in a paper published in European Neuropsychopharmacology in January 2015.3 The curcumin intervention and placebo were each associated with differing influences on certain biomarkers, and higher levels of plasma endothelin-1 and leptin at baseline were linked to greater improvements in IDS-SR30 scores after treatment with curcumin, leading the researchers to conclude that “(p)lasma concentrations of leptin and endothelin-1 seem to have particular relevance to treatment outcome.”