Cannabis and Mental Health:correlation vs. causation

I was reminded of the adage, "Correlation does not imply causation," when I read this abstract.

This paper investigates whether cannabis use leads to worse mental health. To do so, we account for common unobserved factors affecting mental health and cannabis consumption by modeling mental health jointly with the dynamics of cannabis use. Our main finding is that using cannabis increases the likelihood of mental health problems, with current use having a larger effect than past use. The estimates suggest a dose response relationship between the frequency of recent cannabis use and the probability of currently experiencing a mental health problem. [emphasis added]

Many of the serious potheads I have known have struck me as people who would have had mental health problems with or without cannabis use.

Comments

[Rebekah K]

It sounds as if your experience is similar to mine: most real potheads I know smoke it as a form of self-medication for their already massive psychological and emotional damages. Of course, there is a strong possibility that it simply exacerbates the problems. Not that it's all that different from alcohol, in that regard.

[eaze]

thats quite amusing seeing as most of the time their isnt even evidence for correlation let alone causation, see http://ukcia.org/wordpress/?p=76 "The Keele Study"