Saffron (Crocus sativus) for depression: a systematic review of clinical studies and examination of underlying antidepressant mechanisms of action

Background Saffron, a spice derived from the flower of Crocus sativus , has now undergone several trials examining its antidepressant effects and, in a recent meta‐analysis, was confirmed to be effective for the treatment of major depression. Objective To provide an expanded systematic analysis of the completed clinical studies on saffron and depression, detailing dosages, extract sources, standardisations, safety profile and treatment duration; and, through a narrative review, to examine its potential antidepressant mechanisms of action. Design In the systematic review of clinical trials, electronic databases were searched for high‐quality, randomised, double‐blind studies, with placebo or antidepressant controls. A narrative review of in vivo and in vitro studies was conducted to examine its potential antidepressant mechanisms of action. Results In the systematic review, six studies were identified. In the placebo‐comparison trials, saffron had large treatment effects and, when compared with antidepressant medications, had similar antidepressant efficacy. Saffron's antidepressant effects potentially are due to its serotonergic, antioxidant, anti‐inflammatory, neuro‐endocrine and neuroprotective effects. Conclusions Research conducted so far provides initial support for the use of saffron for the treatment of mild‐to‐moderate depression. Further research is required to expand our understanding of the role and actions of saffron in major depression. Copyright © 2014 John Wiley & Sons, Ltd.