Stipulated that marijuana, like alcohol (cf. https://www.ncbi.nlm.nih.gov/pubmed/28988578), is bad for developing brains.
—https://www.ncbi.nlm.nih.gov/pubmed/28557129, “Recreational stimulants, herbal, and spice cannabis: The core psychobiological processes that underlie their damaging effects.”
No mention of permanent brain damage here.
those who insist that marijuana use is harmless.
Has anyone here insisted that - or is this a straw man?
Which I have already pointed out multiple times on multiple threads. Given that brain development continues until about age 25, and that 1 of 16 high school seniors reported daily use last year (Monitoring the Future Survey: High School and Youth Trends), this is a real problem.
—https://www.ncbi.nlm.nih.gov/pubmed/28557129, “Recreational stimulants, herbal, and spice cannabis: The core psychobiological processes that underlie their damaging effects.”
No mention of permanent brain damage here.
Establishing permanent brain damage was not within the scope of this paper. It showed that using mind-altering drugs has considerable effect on brain function through alterations in levels of neurochemicals.
Being that I studied mechanisms of toxicology for my PhD, I can say that substances which cause short term effects on function (whether it's brain function or some other organ system) do cause permanent damage when those effects are prolonged. In some cases--e.g. dioxin poisoning--the activation of a completely natural and common pathway becomes lethal when that pathway is prevented from shutting down after activation. I also have to consider other consequences of constantly activating these neural pathways: for example, epigenetic alteration of the DNA in cells causes essentially permanent alterations in their functions, and effects in other cell populations caused by alterations of brain hormone productions. Etc.
Has anyone here insisted that - or is this a straw man?
That has been the theme of NORML ever since I've heard of the organization, so at least for the last 30 or 40 years. That is also the most common rationalization for the legalization of marijuana that I have seen from legalization proponents here on FR. They keep claiming that it is safer than anything else someone could be using. The fact is that if a substance alters brain function to the point where behavior and perception are altered, it is toxic. And toxic substances can cause permanent damage.