[someone_welsh]

YMMV; Annecdotes != data; correlation != causation etc.

but I've known a lot of modest, moderate and heavy recreational ket users - It's been quite a popular recreational drug in the UK for about 15 years. I would perceive (being not a doctor or anything useful) that the proportion of them which are depressed in some way is a noticeably higher than the rest of the people I've ever met.

It's an addictive drug (perhaps not physically, but definitely behaviourally/psychologically). In my opinion it grossly interferes with peoples' ability to interact with those who don't partake. I find it difficult to recall a single example of its use improving someone's well-being - the converse in fact.

Anyway, just adding my observations/bit of life experience.