Haven't been down this road in 25 years, but I don't think I've ever felt as deep of depressive symptoms as the week or so after taking LSD. I have suffered depression my entire life, but LSD certainly never helped, and probably worsened. Buyer beware.
I get very wary of some of the coverage of this stuff, it all seems very reductionist and simplistic.
I suspect that the positive effects people are having from these things ultimately comes down to two things:
1. the revelation that they can feel a different way, as a result of having the emotional and perceptive aspects of their brain all frazzled (in somewhat random ways) for a period of time.
2. the genuine upside that some psychedelic experiences can and do show how beautiful the world can be. Standing in a quiet field in the spring, or in some mountains, or in a forest in the fall is and watching a flock of birds fly by and hearing the insects sing etc is always an amazing experience, but these chemicals can make you far more sensitive to perceiving that, for a time. And in a way that can stick with you your entire life. Being reminded that the world can be beautiful, and experiencing that at a deep emotional level... may be the best antidote to depression for me.
But they can also really mess you up. I've watched a friend lose total contact with reality, start ranting incoherently, and begin trashing my apartment and wrecking my stuff. I've seen people become total anti-social assholes. I've seen it bring out severe paranoia. And, quite often, pronounced arrogance or elitism.
And I worry it's just more "this chemical will quickfix you", while in fact our brains are so social and community driven and that aspect gets ignored rather than dealt with... And on that note I'd argue that's probably one of the aspects of the positive effects seen in MDMA treatment, in that it definitely does encourage an empathetic and social focus from the individual, or at least it feels like it.... for a time. (But also at the same time, some of the most self-focused and shallow behaviours I've ever seen, so ...)