As others have said, it depends so much on the therapist. I've had talking therapy four or five times over the last thirty years, but only the most recent therapist I saw was really any help. The difference between her and the others was that she had experience of working with autistic people, and it made a huge difference (the possibility I might be autistic had been suggested shortly before this referral.)
I think this is down to several things...
1) Most therapists are used to dealing with people with a temporary mental illness (e.g. depression). A common experience with the other therapists was for them to try and have me recall "better" times from earlier in life, and I just didn't get what they meant by "before I was like this". If I tried to point out that I felt as if my traits had always been present, it was just hinted that I was being "defeatist". The autism aware counsellor was much more realistic about "managing" problems rather than trying to restore a mythical "older, better me."
2) I have significant alexithymic traits, so when asked "how did X make you feel?", I often didn't recall any particular emotion, or there was an emotion there but I couldn't identify it. This was often deemed to be some kind of repression or evasion, when "I don't know" was actually the honest answer. In contrast, the autism aware counsellor would work with me to help me identify the emotions that I couldn't categorise.
3) Misreading autistic traits. One counsellor in particular could be very melodramatic about how "sad" it was that I spent a lot of time alone with my special interests, when I was already fully aware that it was both innate and a coping mechanism, and not something that made me "sad". The autism aware counsellor instead encouraged me to use this coping mechanism more wisely while acknowledging that it can be a valuable tool for managing anxiety.
4) Putting everything down to "negative thinking". It wasn't until seeing the autism aware counsellor that I was able to convince anyone that the people around me really do treat me differently to others and very obviously do notice things like my strange posture/gait, social faux-pas etc. Previous counsellors' efforts to "correct my negative thinking" just came across as gas-lighting to me. Having these things taken seriously made it much easier to stop hiding behind my "mask" during the later counselling.
So I do think that psychotherapy can help, and I would have it again, but I would insist that I see a counsellor who understands that the job has to be done differently when dealing with an autistic patient.
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When you are fighting an invisible monster, first throw a bucket of paint over it.