[gewrtw45]

> The team found that persistent marijuana use was linked to a decline in IQ, even after the researchers controlled for educational differences. The most persistent users — those who reported using the drug in three or more waves of the study — experienced a drop in neuropsychological functioning equivalent to about six IQ points (PNAS, 2012). "That's in the same realm as what you'd see with lead exposure," says Weiss. "It's not a trifle."

> a number of studies have found evidence of brain changes in teens and young adults who smoke marijuana. In 2013, Rocío Martín-Santos, MD, PhD, at the University of Barcelona, and colleagues reviewed 43 studies of chronic cannabis use and the brain. They found consistent evidence of both structural brain abnormalities and altered neural activity in marijuana users.

https://www.apa.org/monitor/2015/11/marijuana-brain

[eikenberry]

Given that they use IQ as a measure also goes to show how little they understand the effects at this point. So take this all with a grain of salt. The best evidence at this point is that adolescent use has some effect on long term memory formation, but even that needs much more study to be understood it. Nothing in the brain works on a simple better/worse scale.

[riversflow]

Yeah, I’m highly skeptical that marijuana makes you legitimately more dumb. If I had to guess, I’d suspect that there are other factors that lead to this result. I’m skeptical because I have seen friends and acquaintances who were “dulled out” by drugs during this period of their life. While many of them were “heavy users” of marijuana, all of them were dulled from other psychotropic drugs(ecstasy being the big one), and most of them lost more than 6-8 IQ points. More like 20+ points.

If anything, I’d say that marijuana use tends to make the brain more doubtful, even of itself. In real life this is a mostly positive trait, but it is punished by the IQ test I think.

[jbob2000]

That's great, but what does that actually mean for someone? Does it mean that they are less happy? Does it mean that they earn less money? Does it mean they have less meaningful relationships?

I understand the mechanisms behind marijuana use, but what is the real effect on a person's life?

[throwawaypa123]

You can't really A/B test humans. Best thing that could be done is twin studies and even those have flaws.

By the way your line of questioning implies an agenda. I don't have an issue with that, but thought I'd highlight that for you.

[jbob2000]

Everyone has an agenda. What agenda do you think I'm pursuing?

Do you think it's one of harm-reduction? Or legalization in pursuit of business opportunities? Or legalization for recreation? Or for medicinal use? Or is my agenda that I have another product in mind that solves all of these things without the side effects of marijuana?

[throwawaypa123]

I can appreciate the perspective of "everyone has an agenda".

Some people attempt a almost a fact based conversation that is an exploration of a topic. Others have an opinion they want to push on others. I don't even try to figure out what someone agenda is. I look that there is one and stop focusing too hard right there and then.

I also suspect, I'm not the only one who operates like this.

If I have an agenda, it is to limit emotion in communication and make things more fact based.

This communication is likely to fail.

To reiterate, many people don't care to figure out what the agenda is and just ignore those who has one. Here i'm using agenda to stand for the typical partisan politics or other "normative" behavior.

[yonaguska]

From the linked article

> Heavy marijuana use in adolescence or early adulthood has been associated with a dismal set of life outcomes including poor school performance, higher dropout rates, increased welfare dependence, greater unemployment and lower life satisfaction.

[jklinger410]

Considering that Marijuana is illegal, this seems impossible to prove.

Show me the development of a teen in a society where open marijuana consumption is a non-issue to compare against.

[thatcat]

Right - you can't use drug tests to unfairly weed people out of employment, then list drugs as the cause of unempoyment and poor life outcomes.

[thaumasiotes]

https://www.amazon.com/dp/B00RTY0LPO/