Does puffing on joints lead to developing schizophrenia, or are people at risk for the long-term mental disorder more likely to use the drug as a form of self-medication? These questions were raised by recent findings showing that people who are more likely to suffer from schizophrenia may also be prone to try marijuana during their lifetime, News-Medical.net reports.

For this latest report, scientists from the United Kingdom’s University of Bristol’s School of Experimental Psychology decided to use Mendelian Randomization (MR)—an evaluation technique that explores genetic differences in individuals’ DNA to determine causal relationships in research experiments. In this study, scientists said they used MR to account for other traditionally observed social factors that might affect the association between cannabis use and the risk of developing schizophrenia.

“Our results use a novel method to attempt to untangle the association between cannabis and schizophrenia,” said Suzi Gage, PhD, a research associate with the institution’s integrative epidemiology unit. “While we find stronger evidence that schizophrenia risk predicts cannabis use, rather than the other way around, it doesn’t rule out a causal risk of cannabis use on schizophrenia.” 

In addition, scientists stressed that more research must be done with gene variations that predict how heavily individuals might use cannabis. Researchers said they wanted to examine the causes and effects of heavy marijuana use, rather than just folks’ initial use of the drug, so they could identify subpopulations of cannabis users who may be at a greater risk for schizophrenia.

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