The biggest antidepressant effect of SSRIs and SNRIs comes from the upregulation of BDNF, not serotonin. Serotonin rises beginning on the first dose, but BDNF

The biggest antidepressant effect of SSRIs and SNRIs comes from the upregulation of BDNF, not serotonin. Serotonin rises beginning on the first dose, but BDNF takes longer, which is why you have to take them for at least 4-6 weeks, sometimes longer, before noticing benefits. It's also one of the reasons why exercise is antidepressive, and many other things. But antidepressants increase BDNF more consistently than exercise, so for some, exercise is not enough. Antidepressants are effective for lots of people. Those saying otherwise in the article...I have no clue where their comments came from...do they have any clinical experience? Also worth noting: psylocibin and LSD are microdosed to give an antidepressant effect, and they both do two similar things: activate serotonin receptors (psylocibin and LSD I think mainly activate 5HT3, and probably other serotonin receptors) as well as increase neuronal rewiring/growth (one through BDNF, the others through a change in perspective and other mechanisms I'm not versed in).