I had thought of that many times, tried to hope it was true, but here's the problem with that theory:
1. I bought the sack from a trusted source
2. I had smoked from that same sack days prior without any effects outside the normal newbie weed experience
3. My mom had no kind of reaction smoking the same stuff, and we examined it afterward and noticed nothing strange about the weed
4. In the hospital, a toxicology report was ran and only found a small amount of weed and alcohol in my system
The only possibility we could think of was that a strange kid I didn't know too well who was at my house that night may have slipped something in my opened drink while I was away, just to be a jerk I guess, but that still doesn't explain why nothing showed up in the toxicology report. Given, the test doesn't look for everything (i.e. LSD), but the scenario seems unlikely.
A month later I tried smoking pot again, convinced that the blunt I lost my mind on was laced after all; however, the same thing happened (only on a much smaller scale). This was the start of my depression. I tried weed again a year later to see if I was able to handle it, and although I experienced some euphoria, the same sense of panic, dread and depersonalization overwhelmed me, albeit only mildly frightening in comparison to the two prior trips. That was the last time I've ever touched pot (roughly four years ago), but things haven't been the same since that first horrible experience.