My brother is on the spectrum and he had a very bad reaction the first and only time he tried pot. It was funny at first, then it quickly got frightening.

My gut instinct (based on nothing except reading this and, well, my gut), is one of two scenarios: someone dosed her on something like LSD or PCP, and then came back for her later. OR that they just dosed her with bad intentions, and then she wandered off in a panicked state in the middle of the night.

I know that friends and family are often suspects (for good reason), but I also think it's possible for loved ones to be confused and irrational when they're in a state of panic.