In the issue of The Week with the fish story (below), there is also a piece on how pot smokers develop psychoses. Apparently, picking up the habit as a youngster is bad, bad, bad. At least if you hope to avoid delusions and hallucinations.
Seriously, a study found that starting to smoke pot before age 15 makes you twice as likely to develop schizophrenia. Who =doesn't= start to smoke pot before age 15? This study may have looked at things from the wrong end. Maybe people who tend toward psychotic disorders have a greater tendency to start young with the hallucinogens.
You know, this study was from Australia as well. They should have done the study in Michigan. The building manager where my sister and I lived in Pontiac was a study in and of himself of pot smoking. Don't think he was psychotic, but I am amazed that he remembered each night where it was that he lived.