PENNSYLVANIA: There exists “minimal evidence” in support of an association between cannabis use by itself and the onset of psychotic symptoms in young people, according to data published online ahead of print in the Journal of Adolescent Health.
Investigators from the University of Pennsylvania, Department of Psychiatry assessed the relationship between drug use and the onset of psychotic symptoms in a cohort of 4,171 young people ages 14 to 21. Authors reported that “neither frequent nor early cannabis use predicted increased odds of psychosis spectrum classification” after researchers adjusted for potential confounders (e.g., concurrent use of other substances, comorbid psychopathology, and trauma exposure).
They concluded, “Overall, we found minimal evidence for associations between cannabis use by itself and psychosis spectrum symptoms.”
The findings are similar to those of a 2015 longitudinal study reporting that early-onset cannabis use is not positively associated with a greater risk of psychosis or other mental health disorders in mid-life.
A 2016 literature review published in the journal Current Psychiatry Reports concluded that cannabis use likely does not cause the psychosis, but rather, that subjects susceptible to the disorder may be more likely to engage in habitual use of the substance.
There’s been a long and heated debate about whether marijuana actually triggers long-term changes in a person, both neurologically and psychologically. Some research has found that pot is linked to psychotic symptoms, and it’s certainly been linked to schizophrenia across multiple studies.
However, it’s a bit of a chicken-or-egg problem, since it can be difficult to tell which is the pre-existing “condition,” the pot smoking or the psychological/psychotic symptoms. Now, a new study from King’s College London finds that smoking skunk, a high-potency variation of pot, is linked to changes in the white matter connections between the two hemispheres of the brain. And this seems to be true whether a smoker experiences psychosis or not.
Skunk has higher levels of the psychoactive compound Δ9-tetrahydrocannabinol (THC) than “regular” pot, and has become much more prevalent in recent years, as people seek out more potent versions of the drug.
The researchers scanned the brains of 56 people who had sought treatment for a first episode of psychosis, and 43 healthy controls. The team looked at the density in the brain’s corpus callosum, the vast network of white matter tracks that extend from neurons in one hemisphere to cells in the other. Damage to the white matter connections means less efficient communication between brain cells, which itself can be linked to cognitive problems.