Neurologic damage from phychotropic drugs?

Factual Questions
1

No, it’s not to do with my own plans, so don’t tell me not to do them.

I have a good friend who is what one might call a “seeker.” He’s been into meditation and yoga for decades, but in the last couple of years he got into high voltage hallucinogens as an aid to whatever spiritual quest he’s on. He went to Gabon and did a lot of Iboga, and he’s been to South America at least twice to do Ayahuasca. He has taken huge quantities of these drugs. He thinks they’ve opened up whole new worlds for him; no comment from me.

Anyway, I saw him a year ago and he seemed just fine. But 6 months ago I got an email from his brother saying he thought the drugs were messing up his mind. I didn’t think much of it, since his brother has always had a tendency to see things that aren’t there. However, today I got the first email of any length I’ve had in a long time from the guy, and it was a mess. Certainly nothing I’d expect from someone who is a Ph.D. I knew what he was saying, but the sentences just didn’t work. They reminded me very strongly of another friend of mine who died from frontotemporal dementia, which fairly rapidly robbed her of her ability to speak. It was like the early-middle stages of her disease.

So, my question is, is there reason to be concerned here? Maybe he was just tired and not paying much attention to what he was doing, I’d like to think. But is there evidence that he could have done himself real neurological damage with all these drugs? If so, would such damage be known to be reversible or not. I’m really quite worried about this. If you have cites, that would be good as well. No opinions not based in research or personal experience, please.

2

I don’t have the data about your friend’s age or past history or just how the letter looked odd (different patterns of expression are indicative of different things), but wrt your question, it is entirely possible under a number of different guises. He may have had a brain primed for drug-induced psychosis, or he may have a psychotic disorder of another sort, or he may have been simply using substances around the time that he wrote you. How permanent these effects are requires more of the above noted type of data, and a little scanning might not hurt either.

3

Gorgonzola: I’m not really after a diagnosis, as this isn’t the place for one. I’m just after reliable information, which is always hard to find when hot-button issues like drugs are involve.

But, to answer you questions, he’s in his mid 50s. The email has lots of sentences like this: “Ed is going to be in Dallas and least on the afternoon of in the morning of June 20th.” I doubt that he’s using drugs, as he doesn’t break the law. And he’s not much of a drinker, one or two beers being the most he consumes.