Do you mean that your special interests "pick" you rather than the other way round?
I spent 9 months or more totally obsessed with learning about autism after the penny dropped that I have it, and I blogged so much about it. Then, almost as suddenly, I tired of talking about it and deleted my blog.
I went through a hellish period of 3 or 4 years when I didn't seem interested in anything, and addictions took the place of interests. Which told me that my special interests are good for me .
Generally I have about 4 or 5 interests that I do in rotation, maybe a couple of years each on average. But as I'm getting older, things are getting less intense - which sounds good, but might not be.
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Midlife ASD realisation - waiting for formal diagnosis.
PhD & material success, burnout, recurring depression.
Finally stopped sending Christmas cards 2018.
INTP
AQ34; EQ16; RQ21
RAADS-R 145
Aspie Quiz @ rdos.net
Your neurodiverse (Aspie) score: 129 of 200
Your neurotypical (non-autistic) score: 86 of 200
You are very likely neurodiverse (Aspie)