A couple of key words have been used here that flag the probable actuality underlying the statements.
Many persons who are mentally ill self - medicate. Cannabis is a common drug for self medication. If you are crazy and consume cannabis, it is not the pot that made you crazy in the first place. Same thing if you substitute alcohol in what I just said.
Another factor here is the fact that about 90% of what we "see" is created/manufactured by our brain from the raw information input from our eyes. Any irregularity in that system will generate "hallucinations", especially in poor vision situations.
Another factor is our minds ongoing effort to create order from sensory input. This subsystem feeds back into the one I just mentioned above, so you "see" an alien where there is in actuality just a human being in poor lighting. The basic human mental characteristic of forcing order on disordered input generates a lot of emotional uproar on an ongoing basis - flying saucers, ghosts, magic etc.
Last, but certainly not least,
...The New Zealand scientists said their study suggested this was probably due to chemical changes in the brain which resulted from smoking the drug.
Note the extensive use of qualifiers in this statement:
"scientists
said"..."study
suggested"..."
probably due to"..."resulted from
smoking" one
pivotal sentence with five
qualifiers placed there as 'escape clauses' just in case someone questions the study "results".
If this had been an
actual study result, it would have said something more along the lines of:
...professors A and B of the neurobiology department at the university of Perth in Australia state in this months issue of the Journal of Professional Neurobiology that their 2011 study of 20,000 subjects firmly establishes that delta nine tetrahydrocannabinol prevents efficient re-uptake of serotonins in neural synapses resulting in the subjects developing schizophrenia..
(^ this is an example, NOT a serious scientific paper being submitted for peer review.)
Anyone who has read a few scientific papers will recognize what we refer to as "hooey" in that first statement. (My example I freely admit is hooey as I just made it up) Anyone familiar with contemporary cannabis politics will be aware that there has been a conservative backlash against the recent loosening of cannabis laws in Great Brittan. The ammunition the conservatives have been using is a series of flawed pseudo - scientific 'studies' out of New Zealand. These 'studies' have been resurfacing an a constant basis for several years now both on their own and buried in "meta - studies" where several flawed studies are reviewed, combined and restated as a "new" study. Thus far though, all of these New Zealand 'studies' that I have read have been based on a single study done on a small self - reported sample set of a few hundred aboriginal people. Self reporting is problematic in serious studies, and the agenda I perceived on that one was racial in objective - it seemed meant to somehow prove that the native Maori people were inferior to the European - descended folks there.
I enjoy the testimonials and anecdotes, recognize the flawed studies because I have seen them so many times now and get a good laugh from the jokes. This is one of my research areas though, as most of you are aware, and I can't let hooey go unchallenged.
I call "hooey" on the statement that cannabis usage causes mental illness and challenge anyone who disagrees to hork up a real study to back up their opposing viewpoint.
As usual I will be glad to submit titles of several serious scientific publications that address this issue, beginning with the "United States National Academy of Sciences School of Medicine Report to the US Federal Government on Marijuana and Medicine". (spoiler: they didn't find any association between consuming cannabis and developing schizophrenia)
