Earlier quoted context omitted.
Of course you're right, which is exactly why I didn't write that . Again: the paper might be correct, but past experience has taught me to be skeptical.
https://news.ycombinator.com/item?id=9156257 I was bothered by this study, and particularly this bit: "After adjusting for sociodemographics, other drug use and childhood depression, we found no significant associations between lifetime use of psychedelics and increased likelihood of past year serious psychological distress, mental health treatment, suicidal thoughts, suicidal plans and suicide attempt, depression an…
>Past year mental health indicators new to this study were suicide thoughts, suicide plan...[etc]
So, it looks like 'past year' applies to all of the terms. I think the study was looking at the long term effects, so if people who quit long ago didn't report any issues, that would support the thesis that 'taking psychedelics doesn't affect long term mental health'. I'm generally not a fan of studies about illegal activity that use voluntary surveys, but this one doesn't look poorly run. However, once you start putting maths to psychology, things get weird very quickly and it's difficult to tell what's valid and what isn't.