My diagnosis is ASC level 1, but my diagnostic report still indicated particular areas where they felt I needed support - including; occupational therapy for executive function problems, autism specific counselling for anxiety/depression, and support to find and keep employment.
Even more important, IMHO, are the kinds of support described by B19 and xatrix26 - the day to day support to help deal with the added stress of living in an "alien" world. This can be so much harder to find when family, friends and colleagues are nearly all non-autistic. Even if they wish to, they are less capable of helping us with those things than usual because they cannot see our problems from an autistic perspective, and so offer us help which is not suited to an autistic mind. In this way, it is quite possible to still feel extremely isolated and depressed even when there are people around who are sincerely doing their best to help. Their attempts to help can even make things worse sometimes, when their well-meaning advice only results in frustration by drawing our attention to traits which make us unable to take their advice (which we have often heard and tried already many times before.)
Like many other late diagnosed people, I have spent decades limping from one crisis to the next, having acute burn-outs every few years from trying to cope by myself, and receiving ineffective "treatments" from mental health professionals who did not identify my autism or how it was the root cause of my mental illnesses. That has been a recipe for extremely poor self-esteem, chronic anxiety and depression and, at times, thoughts of suicide - not to mention the practical problems with housing and finances due to being unable to sustain a job and having difficulties dealing with bureaucracy.
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When you are fighting an invisible monster, first throw a bucket of paint over it.