There is good evidence as well that emotional memories are hardest hit. The laying down of such memory traces is, of course, a key step in the process of emotional learning, ie emotional maturation, ie growing up.
This is evident in the myriad adults who began their MJ habit in their mid teens, and are emotionally stuck there decades later.
It is also the reason why, if a patient comes to me (a shrink) and wants psychotherapy/counseling, and is smoking even a little bit of MJ, I tell them they can have psychotherapy or they can have psychotherapy (emotional learning), but they cannot have both, at least not from me. For me as a doctor, it’s not not at all a legal or even a moral issue - the two are simply incompatible. Psychotherapy simply won’t work in someone using MJ. It also presents a complicating factor if I prescribe meds. In private practice, I have the luxury (at least for now) of selecting who I will and who I will not work with, and if a patient is using MJ and won’t stop, I simply refer them on.
In the 1930s into the 1950s the only people who smoked pot were some blacks, some Mexicans, and some jazz musicians. Pot is a 3rd world intoxicant and suitable for the 3rd world where it is natively from. You should smoke pot if you want to have a 3rd world mentality. If you want to participate in traditional European civilization that advances in science and technology then alcohol is your intoxicant plus it has a history going back to the Hebrews and the Bible. Where wine is often mentioned but (so so sad is it not?) marijuana is never.
By way of contrast, hashish smoking has been common is many Muslim cultures, helped along by the Koranic ban on alcohol
Are you saying that psychotherapy is ineffective only against those actively using MJ, but works fine in cases of practicing alcoholics or others actively using licit or illicit drugs?
The truth is that being addicted to any drug arrests emotional development and this effect is not limited to just MJ.