Iovieno N, Dalton ED, Fava M, Mischoulon D. Second-tier natural antidepressants: review and critique.   Journal of Affective Disorders. 2011; 130(3):343-57.

This article reviews some of the lesser-known natural products with scientific and clinical evidence for their role in various types of depression including Rhodiola rosea, chromium, inositol and 5-Hydroxytryptophan (5-HTP).  The herb Rhodiola rosea may increase resistance to stress, trauma, anxiety and fatigue which can be especially helpful in treating fatigued or lethargic depression, and may help alleviate some of the common side effects of conventional antidepressants. Chromium has a beneficial effect on eating-related symptoms of depression, and may be a valuable agent in treating atypical depression and seasonal affective disorder. Inositol may be useful in the treatment of bipolar depression when combined with mood stabilizers. Evidence for the clinical effectiveness of 5-HTP is promising but still preliminary.  Further study is warranted.

Darbinyan V, Aslanyan G, Amroyan E, et al. Clinical trial of Rhodiola rosea L. extract SHR-5 in the treatment of mild to moderate depression. Nordic Journal of Psychiatry. 61(5):343-8, 2007.

This 6-week randomized double-blind placebo controlled trial assessed the safety and effectiveness of standardized extract of Rhodiola rosea L. in patients with mild to moderate depression. Three groups were studied: group A: 31 patients received two tablets daily (340 mg/day), group B: 29 patients received two tablets twice a day (680 mg/day), and group C: 29 patients received two placebo tablets daily. For patients in groups A and B, overall depression, insomnia, emotional instability and somatization (the expression of psychological difficulties through physical symptoms), but not self-esteem, improved significantly following Rhodioloa rosea L. The placebo group did not show improvements. No serious side-effects were reported in any of the groups. Rhodioloa rosea L extract showed anti-depressive potency in patients with mild to moderate depression when given in dosages of either 340 or 680 mg a day for 6 weeks.