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Lies, Damned Lies, and Statistics

April 16, 2019

Greetings,
 
Cannabis is a hot media topic, as even die-hard journalists tire of Russian collusion stories. We see the whole spectrum – from cannabis as a great panacea to cannabis as a Biblical scourge. As we attempt to sort out this dichotomy, we are reminded of Mark Twain’s popular saying that “there are three kinds of lies: lies, damned lies, and statistics.”    
 
Enter the recent NY Times article “What Advocates of Legalizing Pot Don’t Want You to Know”. As advocates of pot legalization, we figured we should know! The big reveal is a 2017 National Academy of Medicine study concluding that cannabis is linked to higher risks of schizophrenia and other psychoses. The author cites the rise of serious mental illness nationally (especially with 18- to 25-year olds – the most likely users of cannabis), which also has an associated linkage to violence. Lastly, the author draws a parallel to the opioid epidemic saying “decades ago, many of the same people pressing for marijuana legalization argued that the risks of opioid addiction could be easily managed.”
 
We take health warnings and corporate responsibility extremely seriously at Presidio View. However, as we are neither doctors nor medical professionals, we knew we needed to seek one out. So let’s see what Dr. Earleywine – a former guest contributor, professor of psychology, and overall cannabis expert has to say.
 
Lately, the idea that marijuana makes people schizophrenic seems to sell books, but, in a nutshell, this is untrue. Misunderstandings about genetic risk, inadequate measurement of the use of hard drugs, and poor definitions of psychosis have led researchers to wrong conclusions. Sadly, since cannabis holds promise for treating schizophrenia, these mistakes are costing society dearly. 
 
Only about 0.5% to 1.0% of the population has the disorder. My friend Dr. Sarnoff Mednick showed, through decades of complex research, that a combination of multiple genes and multiple stressors have to interact for someone to develop schizophrenia. The stressors can even happen before they are born.
 
If marijuana use increased schizophrenia, we’d expect rates of use and rates of the disorder to hang together. If one country had a lot more people using marijuana than another, we’d expect that place to have more schizophrenics. But nope. And in the same country, we’d expect more schizophrenia during periods when more folks used marijuana. But nope. In the UK, for example, marijuana use goes up and down but schizophrenia always seems to hover just below 1%.
 
So where did all the clamor about marijuana and schizophrenia come from? If researchers ignore hard drug use and loosen the definition of schizophrenia, they can get modest correlations between marijuana and psychotic symptoms, grab headlines, and help journalists sell books. But careful readers can see through the nonsense. In fact, over 10 years ago in my lab, we showed that controlling for hard drugs eliminates any link between marijuana and psychosis.  In addition, schizophrenia is incredibly rare, making it hard to predict. But “schizophreniform disorder” and “schizotypal personality disorder” are more common, and the measures used to assess these can be incredibly biased. As I showed in 2006, cannabis users misinterpret some items and end up looking psychotic even when they’re not.
 
Truth be told, the confluence of cannabis and schizophrenia is complicated and may even be from people who have the initial symptoms of schizophrenia turning to cannabis in an effort to self-medicate. This idea is particularly interesting as a subset of schizophrenics has been shown to actually get better from cannabis. I wish preventing schizophrenia were as easy as keeping marijuana out of the wrong hands, but it’s not that simple. 

 
Not that simple indeed! We thank Dr. Earleywine for his thoughtful and well-researched perspective. As the public opinion battle over cannabis rages on, we encourage you to gather all the facts – regardless of which side you land on. Mark Twain insists on it.
 
Thanks for tuning in, and we look forward to providing you with more industry and business updates in the coming months. Until next time!
 
Cheers,
Mike and Kip
Co-Managers, Presidio View Capital

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