[Passthepeas]

I'm sure it sounds like a broken record at this point, but "correlation =/= causation". It is possible that many that abuse cannabis are also more likely to engage in other activities that could contribute to brain aging. Of course it does not mean there is not causation either, but nonetheless more research is needed to be able to say definitively that it contributes more to brain aging than alcohol. Also as others have pointed out, the researchers definition of "abuse" is not defined.

Edit: also would like to add that it is quite common for people with mental illness to self medicate with cannabis, there are enough variables here to make one want to pull their hair out