Autism doesn't go into remission. It's not "curable", but it is treatable. People on the spectrum can get better at coping and controlling their condition and traits, which can make them appear more normal, but too much stress makes the the control slip, and our traits then tend to manifest themselves again. Also, even though we may be able to control and cope somewhat out in public, we need to let go of that control when we are in private, so we can vent, and then recharge ourselves. So the docs and therapists are seeing the controlled, public face, and not your true autism condition. Also, anyone who thinks they can diagnose anything about autism in just five minutes is either an incompetent idiot, or delusional. Autism is a very complex condition, with many possible variations, and many possible traits. It takes more than five minutes to figure out anything about such a complex condition. Don't see that idiot again. Insist on seeing someone with autism experience who will spend the time needed to do a proper diagnosis.
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau