I don't really know. I think because i can usually function, and seem ok to people, even when i'm not. I always had other explanations, like using substances, but the symptoms continued substance free, and continued getting worse sometimes. I spent time in a treatment center at 20-21, with a misdiagnosis, although i don't know how they missed it, because it seems obvious looking back. But I didn't figure it out til age 29, when i had a severe episode, and nearly destroyed my marriage