You keep hogging bandwidth talking about some old study that doesn't really prove diddly. If pot smokers are four times as likely to develop serious mental illness then you would think that there would be substantially higher rates of mental illness in states with substantilly higher per capita marijuana use. Is there? Of course not, in fact it's really th other way around.
I saw this study you were talking about before and found it highly suspect. It did not prove causation. Just out of curiosity I did some checking into statistics on marijuana use and serious mental illness. The U.S. Department of Health and Human Services' Substance Abuse and Mental Health Services Administration (SAMHSA) collects data on both mental health issues and drug issues. My thinking was that if marijuana really causes serious mental illness, there would be correspondingly higher rates of mental illness in states with higher rates of marijuana use. Doesn't that seem logical?
First I looked at the state with the highest past month marijuana use, New Hampshire. In that state 10.23% reported use of marijuana in the past month on the last survey and and according to SAMHSA 8.8% of New Hampshire's population suffer from serious mental illness compared to the national average of 8.76%. Then I looked at the state with the lowest marijuana use, Utah. There only 4.00% reported past month marijuana use but SAMHSA says 10.97% suffer from serious mental illness.
Now, that was interesting to me but there are too many variables that can come into play that call into question the results from just two examples. So, I dug a little deeper and looked at the ten states with the highest and ten states with the lowest marijuana use. The national average past month marijuana use was 6.18%. The top ten states averaged 8.93%. Serious mental illness in these states averaged 8.73%, compared to the national average of 8.76%. Serious mental illness in the ten states with the lowest marijuana use averaged 9.44%, even though past month marijuana use only averaged 4.73% in these states.
Why is it that the states with the highest marijuana use actually lower rates of serious mental illness than the states with the lowest marijuana use? I honestly don't know. I don't think you could conclude from that that marijuana use reduces mental illness, but it certainly does call into question research that shows that marijuana use drastically increases mental illness.
Here are the tables I used from SAMHSA's 2003 NSDUH. The link to the past month marijuana use by state is here: http://www.oas.samhsa.gov/2k3State/appB.htm#tabB.3
The link to the serious mental illness numbers by state is here: http://www.oas.samhsa.gov/2k3State/appB.htm#tabB.21