There are generally two reasons to get diagnosed as an adult. The primary one is self-understanding; it's a nice feeling being certain of your neurology, especially when you have to defend it to individuals who don't believe you. It also erases any nagging feelings of doubt you might be carrying around. The second reason most adults get diagnosed is for work or government benefits; they need help that they can't get without proof of diagnosis. If neither of the above apply to you, there's not necessarily a reason for you to get diagnosed. I will say this though; even without seeking benefits, getting diagnosed was one of the best things I ever did; it improved my understanding of myself, and solidified others' acceptance of my condition (before diagnosis, even my mother, who was the one who originally brought my having AS up as a possibility, once said, "Well, you're not diagnosed so we don't really know you have it." She's since stopped saying that.) It also gave me peace of mind; I was no longer tormenting myself over the question of did I or didn't I have it.
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"Survival is insufficient" - Seven of Nine
Diagnosed with ASD level 1 on the 10th of April, 2014
Rediagnosed with ASD level 2 on the 4th of May, 2019
Thanks to Olympiadis for my fantastic avatar!