DSM V wrote:
Diagnostic Criteria for 299.00 Autism Spectrum Disorder
........3. Highly restricted, fixated interests that are abnormal in intensity or focus (e.g., strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests)..........
Of course you don't have to have that at all. In my case I kind of fit the bill, but I don't think my intense interests are particularly unusual. The enduring ones are music and certain aspects of the use of computers. I see nothing unusual about being a musician and nothing unusual about a musician having a strong enthusiasm for performing and recording as a lifelong thing. And my computer interests are more of a means to an end than a great love of the means, though as with music I've come to greatly enjoy operating the skills I've acquired and getting results that (I like to think) not so many people could surpass. Nothing unusual about becoming skilled in a few specialised fields.
My intense interests rarely last longer than necessary for achieving a particular goal. It's just that a musician usually wants to do another performance or make another recording, and a computer is a highly versatile machine that can do all kinds of things quicker, easier and better, so it's not surprising that I'm often developing the techniques necessary to acquire the goodies, and naturally a lot of them are to do with music. It's not my choice that there's no affordable producer and recording engineer who would do the technical legwork while I concentrate on the art.
I just write or find programs and utilities for getting whatever perfectly normal thing I might want, and I'm always interested in reducing the amount of necessary effort to get those things. Indeed, a good computer program essentially provides a way of getting what you want by just pressing a couple of buttons.
So I think it's just that I have a tendency to solve problems myself, by focussing well and thinking clearly and critically. Perfectionism pushes me into working rather longer and harder than NTs might, in order to go the extra mile instead of being satisfied with 90% of the result for 10% of the work.
Being a problem-solver is a big part of me, and I can't imagine life without it, without pitting my wits against whatever discomforts I run into and whatever ambitions I take a fancy to. As such, I've covered a pretty broad range of challenges.
So it's not quite the stereotype of having a chronic, weird obsession to the detriment of normal life. But they're certainly special interests in the literal sense of the phrase - I take a strong (but often temporary) interest in getting the myriads of results that I want.