According to the World Health Organization, depression is experienced by 5% of adults. Anxiety is experienced by up to 30% of adults at any point in their life, according to the American Psychiatric Association. Additionally, the World Health Organization found that depression and anxiety went up by 25% during the COVID-19 pandemic.
Ayahuasca has been used for centuries in the Amazon. According to Dennis McKenna, it was widespread throughout the Amazon Basin, being used by various indigenous tribes by the time it was noted by Western ethnographers of the mid-nineteenth century.  Ayahuasca is a blend of plants (specifically Psychotria viridis and Banisteriopsis caapi).
“Ayahuasca is unique in that its pharmacological activity is dependent on the interaction between the active alkaloids in the plants,” says McKenna.  The medical community is beginning to recognize the value of Ayahuasca for treating addiction, depression, anxiety, and other mental disorders.
In a recent study of 11,912 participants, those who reported “depression or anxiety at time of drinking Ayahuasca, 94% believed that their depression had improved either ‘a bit’ (15%), ‘very much’ (46%), or was ‘completely resolved’ (32%) due to their consumption of the brew. With respect to anxiety, this effect was even more pronounced, with 90% reporting an improvement in symptoms either ‘a bit’ (20%), ‘very much’ (54%), or ‘completely improved/resolved’ (16%).” 
In a study conducted at an in-patient facility, researchers found a single dose of Ayahuasca to be very beneficial; “statistically significant reductions of up to 82% in depressive scores were observed between baseline and 1, 7, and 21 days after [Ayahuasca] administration.”  In fact, the Ayahuasca had “fast-acting anxiolytic and antidepressant effects in patients with a depressive disorder.” 
Additionally, another study showed benefits when used in conjunction with psychotherapy at an in-patient facility. “From pre- to post-treatment, patients showed significant reductions in scores of anxiety and depression. Similarly, patients showed higher scores of quality of life and spirituality upon discharge, which correlated with their reduction in scores of anxiety and depression.” 
There are many more studies showing the benefits of Ayahuasca to treat depression and anxiety. Furthermore, Ayahuasca has shown to be beneficial in treating those with treatment-resistant depression. Combining this medicine with current psychotherapies can optimize the benefits of both.
 McKenna DJ. Ayahuasca: An ethnopharmacologic history. Sacred Vine of Spirits. Ayahuasca. 1998. Times cited=75
 Sarris J, Perkins D, Cribb L, Schubert V, Opaleye E, et al. Ayahuasca use and reported effects on depression and anxiety symptoms: An international cross-sectional study of 11,912 consumers. Journal of Affective Disorders Reports. 2021;4:100098. Doi: 10.1016/j.jadr.2021.100098 [Journal Impact Factor=4.839; Times Cited=16]
 Osório Fde L, Sanches RF, Macedo LR, et al. Antidepressant effects of a single dose of ayahuasca in patients with recurrent depression: a preliminary report. Braz J Psychiatry. 2015;37(1):13-20. doi:10.1590/1516-4446-2014-1496 [Journal Impact Factor=2.44; Times Cited= 401]
 Giovannetti C, Garcia Arce S, Rush B, Mendive F. Pilot evaluation of a residential drug addiction treatment combining traditional Amazonian medicine, ayahuasca and psychotherapy on depression and anxiety. J Psychoactive Drugs. 2020;52(5):472-481. doi:10.1080/02791072.2020.1789247. [Journal Impact Factor=2.54; Times Cited=18]