It’ll be difficult finding an ‘official’ treatment, as research was blocked for the longest time and has just started up again. However there are various legal ways.

There are groups and tribes that provide treatment or rituals, I can’t link anything, but if you have some cash you could look into that. For example ayahuasca rituals are available in Latin America.

Alternatively you could do it yourself, you could visit a place where it is legal like in the Netherlands, where you have smart shops.

You can’t buy them off the street because there is no profit in it. It’s sort of like an anti drug because you won’t feel like taking more, and it’ll likely take you off other drugs.

Your best bet might be to DIY. You can order spores online, which afaik is legal in most places, but look it up to be sure in your jurisdiction. There are plenty of websites describing how to grow them. It’s a slightly involved process but it’s doable and a batch will last you forever.

I can’t overstate enough that you have to respect it. Look up online how to use it properly. Don’t treat it like some party drug. Don’t take it if you have schizophrenia. You’ll need a trip sitter you trust, like a good friend, and you’ll need to be in a place where you feel safe and you can be alone. The best setting is typically nature. Eat healthy before. Not too late in the day. You’ll need rest the next day.

So as you can see it is rather involved. However, if you have chronic depression I can personally recommend it. It’s impossible to describe but perhaps you can compare it to going on a walk with a good friend and having a really insightful talk.