I have known alot of people who smoke weed, and one thing I've noticed, and this applies to the daily smokers especially, almost all of them are in complete delusion about the negative impact it has on them. They become less intelligent, less articulate, less cordinated, less confident, slower, less capable of connecting with others. They also tend to seem like they don't care about anything, they are worse at empathizing and all conversations with them just seem completely disconnected.
I definitely don't think it should be illegal, but I wish people who smoked it were more honest with themselves.. I've tried a couple of times though, that when I've really tried to squeeze the truth out of these deluded people, that they'll start to admit that it does infact impact them negatively, but they just enjoy doing it. I guess that's the case with most addiction though.
Back to the topic: I've seen psychiatry have a profound postive effect on peoples lives. Especially in the case of scizophrenia, where the medication, was the difference between complete chaos, and being able to live a decent life. I know this, because I grew up around scizophrenia, and the medication didn't just change the life of the person with the mental illness, but my life aswell.
I don't doubt that there's alot of cases where medication have been prescribed wrongly, maybe due to errors in the diagnostic process, or that it hasn't worked as intended. But I think the field of psychiatry is positive as a whole. I don't like the stance of trying to dehumanize everyone who works in the medical field, I am certain the vast majority of them are decent people with good intentions.