Autistic people often report that SSRIs don’t work well for them and that they get more severe side effects.

This is not always the case so don’t set the expectation that it’s not going to work for you. Also keep in mind that there’s a sampling bias here - you don’t see autistic people constantly telling everyone “I took SSRIs and it was pretty okay, nothing much to report on really” but the autistic people who have had bad experiences with SSRIs are going to be more vocal about it because that’s just how things work.

As general advice for a person who is autistic or who suspects that they are I’d say that a low dose might well be the sweet spot for you where you get the benefits without so much of the side effects and, if you do increase your dose to do so gradually because if you happen to be unusually sensitive to the side effects like a lot of autistic people report then the typical way that you are directed to increase your dose might be too rapid for you.

Anxiety and depression are really common for autistic people but autism often brings experiences of executive dysfunction, burnout, and catatonia which can resemble depression very closely. My hunch is that there’s a good percentage of autistic people who experience these things but they are under the impression that they are symptoms of depression and so they find antidepressants don’t work for them.

In a similar way, symptoms of anxiety can closely resemble experiences like overstimulation and being exposed to noxious stimuli, masking, suppressing stims, and not meeting your need for stability and predicability in your environment.

If you think that you’re likely autistic I’d encourage you to look into these things at your own pace and to approach symptoms with curiousity and a sort of scientific approach, without any preconceptions, to see if there’s a possibility that your experience might be, say, burnout rather than depression. Or that some symptoms that you experience might be better understood as burnout instead of depression. This is me speaking from hard earned experience - I was far too quick to lump all of my symptoms into common categories like anxiety or depression without really putting in the time to consider whether or not this was accurate and so I wasted a lot of time and effort trying to find the “right” treatment for my depression when half of my symptoms weren’t even depression at all.

idk about ADHD though

ADHD occurs somewhere around the 40% mark in autistic people. (The reverse is not true however - there’s no data indicating that 40% of ADHDers are also autistic.)

There’s a real gap in understanding what auDHD is like and this goes all the way to research. I’m diagnosed auDHD and treated for it (so the chances of this being a misdiagnosis are extremely unlikely) and my experience of it is that the traits of both conditions sometimes mellow out the extremes but sometimes they can aggravate them or amplify them too, so it isn’t something like anxiety and depression where the anxiety tends to override the depression or vice versa, and it’s not a matter of an additional thing like having insomnia plus depression, where your mood is low and you have serious difficulties with sleep. Instead auDHD often feels like a weird blend of symptoms and traits that are often conflicting.

I’m gonna do some shameless self-promotion and link to a post I made about my own internal experience of auDHD here. This is just my own experience, it’s not diagnostic and it’s not intended to be but you might find it interesting. If a lot of it happens to resonate with you then that’s a good indication to consider if you might be auDHD yourself.

Obviously all of this is just stuff to consider, I’m not telling you how things are for you or trying to steer you in any particular direction; you know yourself better than some unqualified internet stranger ever could.