Smaller doses of ketamine (recreational doses) taken via nose tend to alleviate depression and anxiety for me for 1-2 weeks, depending on how much of it I do.

I've been meaning to travel sometime to a clinic for the infusion therapy (that comes with some talk therapy) as where I am now its nearly impossible to source clean ketamine reliably.

Pretty mild doses of psilocybin mushrooms tend to have a longer lasting effect (a month or so), and extremely large doses can work for a half a year or so.