Christina M. Dording and colleagues published in CNS Neuroscience & Therapeutics 14 (2008) the findings of a double-blind, randomized, pilot dose-finding study of a Peruvian plant, Maca root (L. Meyenii), for the management of SSRI-induced sexual dysfunction. It is certainly a small study. They took 20 remitted depressed outpatients (17 women) who had a mean age of 36 +/- 13 years who had SSRI-induced sexual dysfunction. They used two different scales to measure sexual dysfunction. Ten subjects completed the study and 16 subjects (9 on 3.0 g/day; 7 on 1.5 g/day) were eligible for statistical analysis. Those on 3.0 g/day maca had a statistically significant improvement in their scores but the 1.5 g/day did not. Maca was well tolerated and had significant effect on libido.
Sexual dysfunction is one of the most significant barriers to successful treatment of depression with an antidepressant. The only currently available, reasonably reliable remedy are the PDE-5 inhibitors (Viagra, Levitra, Cialis, etc) but they act on male erectile dysfunction and anorgasmia. Benefits for women are questionable and further these agents are quite expensive.
There are definitely reasons to be caustious about the interpretation of these findings. First there was a high dropout rate which could relate to tolerability and second 85% of the subjects were women. The small size could represent a statistically skewed sample and at least 50% were taking one other drug in addition to their antidepressant. Yet, as Darwin comments in another context, "From so simple a beginning...."