I have never done a sleep study, mainly because with the medications I'm currently taking I'm sleeping a lot better, so there doesn't seem to be a need. Even if they found out the exact cause of my sleep disturbances, the only thing they could do for me is medicate me, heh. I was on a medication briefly for insomnia when I was 18, and the doctor said I don't go through normal sleep patters; I wake up during REM, which is why I would vividly remember all of my dreams, and why I sometimes hallucinate when waking up. He gave me amitriptyline, but I found that its efficacy decreased quickly, so I stopped taking it.