BDNF and major depressive disorder: The multiple combined effects of increased cortisol levels, brain-derived neurotrophic factor (BDNF), anti-inflammatory effects, and stimulation of the sigma 1 receptor along with positive mystical experiences during ayahuasca use and the after-effects all contribute to ayahuasca’s potential as an antidepressant for those with significant depression with poor remission by current pharmaceuticals available [26].