I agree with the author. 10 years after this study was done, another UC Berkeley health official wrote about the effects of marijuana he had observed in his students and they confirm this report. I have noticed the same thing over the years with pot users.
One of the most disturbing effects is the inability to judge themselves. Invariably they think they are smarter and sharper than everyone around them, when it is fairly obvious to the "cleans" that they are prone to mistakes, terrible moods, etc. Use of this drug sems to obliviate honest judgement and turn on a switch of denial. Perhaps that is why they like it so much.
If I wasn't so much sharper and smarter than you I would get mad at that.
Guess I'm just in a bad mood.
:>)
I won't claim to be an expert on pot. In fact I've have never used it. Only breathed it secondhand at rock concerts. Speaking of which I noticed that the creativity of virtually all the big names in rock dried up when they hit thirty. Most of them bragged or conceded their heavy use of pot. Which might answer the question of why Paul McCartney's post-Beatle music is so dreadful. McCartney is one of the biggest exponents of maryjane. The only conclusion I can come to is that he and many other leading songwriters of that era fried their collective brains on the stuff.