Well, to be fair, some research on the effects on *developing* brains shows there may in fact be some damage. So, you probably shouldn't toke too much before you exit adolescence. And if you have a family history of psychosis or schizophrenia or anything like that, you might also want to be careful.

For everyone else though, there's quite a lot of info out there now that shows cannabis potentially helps with preventing at least some cancers, and may also be useful for those with osteoporosis. So, pretty much every adult would likely benefit from toking up, even if it's just to reduce risk of some cancers.

We (the human race) need to do a lot more research on the positive and negative effects. Especially the positives, because there are probably tons of positives we don't even fully grok yet. The idiotic laws in the U.S. prevent most such research though, so I guess we have to look to other (smarter) countries to do that research for us.