What do you not believe about the study? Did you read the study?
> In this paper, we presented results of the first empirical study of cannabis’s prevalence, perceptions, and usage motivations in programming environments
I don't think this study says "weed makes you better" or anything like that.
In my (speculative) opinion, it's not "societal pressure" but rather "capitalism pressure" narrating the recent weed uprise. As in, the opportunity to capitalize on weed has been pushing the narrative that it's a harmless cool drug.
The risks of heavy cannabis use are well documented and easily available to those who care to research it. For example, try CTRL+F "cannabis" on https://en.wikipedia.org/wiki/Schizophrenia.
Once again, just like alcohol and tobacco, capitalism wins over public health.