The study was done very carefully over a period of 30 or more years and included a group, who did not use marijuana. The Universities that were involved were top notch.
Since it was a longitudinal study, timespan was a minimum criterion and not a guarantee of being the last word.
and included a group, who did not use marijuana. The Universities that were involved were top notch.
Which still doesn't make it the last word. The researchers themsleves said it’s possible that such elements as child abuse or other trauma could explain the results better than marijuana itself.
The harms of alcohol to the brain are at least as well established, as I showed - so you have yet to present a reason why alcohol should be legal but marijuana illegal.