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.