There’s a large body of research that has shown people who use marijuana also have an increased risk of developing schizophrenia, but scientists have struggled to find conclusive evidence that this correlation necessarily means causation. A new study, published in the journal Nature Neuroscience and involving genetic data from the DNA ancestry database 23andMe, has confirmed that there is a “significant genetic correlation” that indicates the emergence of schizophrenia may lead to a greater probability of cannabis use.
So are people using marijuana to calm the symptoms of schizophrenia, or is marijuana use jump-starting the brain-chemical imbalance that contributes to it? Turns out it might be a lot more complicated than that.
Over the last several years, researchers at the International Cannabis Consortium project have been studying whether certain genetic variations indicate a predisposition towards cannabis use. The new Nature Neuroscience study is the largest of its kind; the researchers analyzed anonymous genetic data from over 180,000 people, culled from either previous studies or from the 23andMe database. The evidence indicating marijuana use can cause schizophrenia was “weak,” the authors wrote, but there was a stronger indication that early symptoms experienced by “individuals at risk for developing schizophrenia … [may] make them more likely to start using cannabis to cope or self-medicate.”
This finding brings important clarity to previous studies that suggested smoking marijuana at a younger age can cause the early manifestation of schizophrenia in people with a genetic predisposition. This new study suggests the opposite is more likely — that early symptoms of schizophrenia can lead a young person to start smoking marijuana. A significant factor that many of these studies struggle to consider are the benefits of marijuana use in coping with those symptoms. One reason could be that evidence of these benefits may be anecdotal, but not necessarily measurable in the ways traditional science considers valid or quantifiable.
However, there is also the fact that many of the studies analyzing the link between marijuana use and schizophrenia are about “risk,” as if both are inherently negative or hazardous. Marijuana use, unlike a complicated mental disorder like schizophrenia, is one that can be controlled, including in many states by law. It makes sense then that even supposedly unbiased researchers would be more inclined towards interpretations of marijuana’s causal effects rather than the other way around.
While there are certainly some downsides to marijuana use — though none which come close to the potential risks associated with alcohol, tobacco and legal prescription opiates — its benefits are becoming more widely accepted. The ongoing spread of legalization, both for medicinal and recreational purposes, has increased opportunity for deeper research into how cannabis can be used to manage symptoms of schizophrenia, including the potential differences between intake methods, like smoking, vaping and edibles.
There already has been significant evidence of the overall health benefits of cannabidiol, or CBD, the plant’s non-psychoactive compound, including its antipsychotic properties. Studies have shown that CBD use by people with schizophrenia led to significant clinical improvements on par with anti-psychotic pharmaceuticals, but with fewer side effects.
While there is still much research to be done into how cannabis’s psychoactive compound, THC, impacts patients with schizophrenia or its early symptoms, marijuana legalization and its associated regulations have made it much easier to adjust the levels of THC versus CBD to meet the needs, be they recreational or medicinal, of the user. That’s good news all around.