Teen Cannabis Use Doesn’t Cause Schizophrenia, a New Study Suggests

Researchers from the University of Minnesota Institute of Child Development conducted a longitudinal co-twin study in which they tried to establish a causal link between cannabis teen use and the risk of schizophrenia in adult life.

To do this, they looked at two cohorts of twins whose cannabis use in adolescence as well as the incidence of cannabis use disorder was documented and later compared with the proneness to psychosis. The results seem to refute the long-held belief that cannabis consumption, especially if it starts early in life, is one of the risk factors for developing psychosis.

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Association vs Causation

Consistent with the previous research, the study found a clear link between cannabis use and cannabis disorder, on the one hand, and psychosis-proneness, on the other. However, things got more interesting in that part of the study where identical twins were compared with each other.

The scientists found that when one of the twins had more cumulative exposure to cannabis than the other, the incidence of schizophrenia wasn’t statistically different. The reason that cannabis use and mental illness have demonstrated such a consistent association across numerous studies may be some other confounding factor.

What Does Matter is the Family History of Mental Illness

Previous studies have established that predisposition to psychotic disorders is hereditary. It was hypothesized that this congenital vulnerability was the overarching cause for both mental issues and cannabis abuse. After all, it is common for those whose mental health deteriorates to mask their symptoms with mind-altering substances.

And with this hypothesis in mind, the authors included molecular genetic data from subjects into the study’s design. Again, the association between schizophrenia and inborn predisposition was there.

Commenting on the results of their study, the authors suggested that policymakers preoccupied with the deteriorating mental health of the society at large stop blaming cannabis and focus on actual causes of psychotic disorders.

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This content is for educational purposes only. The information provided is derived from research gathered from external sources.