SSRls are mostly used as antidepressants and there is a, now we can say it, a little bit old paper by Callaway and Grob, where they alerted about the risk of a serotonin syndrome by the combination of ayahuasca and SSRls, and whenever you go to any people who have some information, specially westerners, they will say "never take ayahuasca with an SSRl" you might die, this is absolutely forbidden 