Some people’s brains don’t respond to drugs and alcohol the same way other people’s do. I don’t get high from prescription narcotic drugs. I get sleepy if I happen to be tired already, but if I’m well-rested, I don’t even get sleepy. I don’t get constipated from them either-- they do work as cough suppressants, and they do relieve pain, but they don’t work all that much better than Tylenol. When I’ve been in post-surgical pain, Tylenol + narcotics was better than Tylenol alone, but I was still in some pain. Other pain, like cramps, Tylenol knocks out easily.
I can get drunk, but I get a terrible headache when I drink alcohol, and I don’t mean a hangover-- I mean it comes on within about an hour of drinking more than about an ounce of wine, or half a beer. I get migraines, and I think alcohol just happens to be a trigger, but in any event, I don’t feel good when I’m buzzed.
Pot just makes me kind of tired, and a little confused. It doesn’t make me feel good either, but I really don’t feel “altered” on it-- I feel like I didn’t get enough sleep, that’s it. I certainly wouldn’t drive on it, but I’m not in danger of hallucinating, or anything. I’ve never tried LSD or heroin.
I’m Jewish, and probably have a good dose of Ashkenazim (I don’t know exactly how much of what kind of Jew I am, except that I have at least some Ashkenazim). Ashkenazic Jews do become addicts sometimes, but statistically, we have lower numbers of addicts than other ethnic groups. (We have our own problems, though, believe me-- when Asperger’s syndrome was a diagnosis, there were high numbers of it among Ashkenazic Jews).
Anyway, there definitely are genetic factors involved in addiction, and one certainly is the basic response to drugs in the first place.