I wonder how many of these are caused by autism vs how many are caused by autistic lifestyles.
This is the main thing I'm wondering as well.
You could even wonder if it comes with autism from day 1 (as in, being born with it) or if it develops later in life because of autism. I mean, I don't think I've been born depressed and in general I'm not a depressed person, nor have I been (yes, I might be a bit more gloom and doom, but that's just me) in general. But circumstances can make one feel really horrible. Extensive bullying is one of those things. Feeling inadequate to actually live a decent life (having a significant other, succeeding in college, landing a nice job, and so on), might contribute there as well. No wonder depression and (attemped) suicide rates are up. If you add in that there's often no understanding by parents and/or friends on someones behavior, just because it doesn't mirror theirs it makes up for more confusion and feeling less accepted.
I guess the people on the spectrum who suffer the least from depression and such are the ones that don't care about social norms at all (or at least to only a minimal degree). They're so engaged in their own little worlds. Perhaps that's why I haven't been overly miserable most of my life as well. And while it doesn't make me outright depressed, having financial worries at the end of the month are detrimental to my mental health as well... just to a lesser degree than outright depression (though I will address this a bit more below).
As for physical health issues; I think the forum thread about daily exercise does underline it a bit. While quite a few do get out, and some might have jobs, there's an amount of people (myself included) that often do the bare minimum for a variety of reasons. Though that's just the overweight issue. And there's probably stuff like diets and more of that kind that often require some external support both through a qualified professional and finances, both things which might be an issue. Finances because; no job might limit your income significantly, and a qualified professional might not be understanding enough to deal with someone on the spectrum.
However, where I see most focus right now by governments as well as healthcare specialists is to get people on the spectrum employed, disregarding all the underlying issues that might or might not have their reasons for being the way they are. Don't get me wrong, having a job and making a living is important, but the moment the focus is on having a job rather than being able to live a meaningful and healthy life with the least complications as possible just doesn't really add to it. Jobs often do create more issues on top of the ones some of us already have. (and looking at some stories on this forum does underline this).
It's interesting though, since I've seen therapists who did focus a lot more on trying to hook me up with a more "stable" life situation that worked for me. All I've heard was, just make with what you have now. Engage in those hobbies and don't deny yourself anything. The last thing we want is you to come back being depressed because you can't keep yourself busy and motivated with personal goals. We're not a daycare nor do we want to be a revolving door. That by itself is good, since I feel it gave me confirmation that I should get into hobbies more (and so I did). The downside obviously is that I'm doing these hobbies at the expense of a government welfare check, that is (at least here) about half of minimum wage (and that number will greatly vary per country). I don't see myself sustaining this all in the long run, though given the low amount of people on the spectrum that are employed (and even worse, employed and happy with their job, since otherwise that'll inexplicably become a festering wound that turns into depression at some point), it's a vicious cycle by itself. I think I'm already a step ahead by understanding the cycle and putting the word out to those involved (social services, therapists and such) that there's a cycle which they are obviously missing since they're not being put in it.