My first thought too. Don't know if it would have made any difference in the end result but LSD and Psilocybin Mushrooms are ranked much safer than Ketamine and unlike Ketamine, aren't addictive.

When I saw the Psychedelics headline I was expecting these two plus maybe DMT. Some people consider Ketamine as psychedelic drug but it's really a dissociative drug.

Physician supervised ketamine therapy has worked wonders for people with PTSD, at least one of whom I know personally.

Otherwise, street ketamine can be adulterated with anything. It is dangerous.

ketamine has become a very popular party drug in the UK so the stigma might have been significantly less, and therefore the perception of safety

well, LSD is not safe either. Of 3 people I took it with, in high dose, for various reasons, only one of us left the encounter better off and largely unscathed. Professional psychiatric help doesn't have great odds either but they're significantly better than an anecdotal 1/4, and when things go wrong people tend to know why and how to help. Leave the research and unproven chemicals to the researchers I guess?

What happened to the other 3?

It varies, some more benign, like short term legal trouble from acting out while on it, while another went down a darker path, like re-joining a cult they'd left. Perhaps what I view as darker path is their light path though, from what I've seen they seem happy.