Systematic Review of the Neurocognitive Effects of Cannabis Use in Older Adults (2019) | Hacker News Reader

Systematic Review of the Neurocognitive Effects of Cannabis Use in Older Adults (2019)

ncbi.nlm.nih.gov

43 pointshaltist48 comments

> Several limitations must be considered when interpreting the evidence reviewed in this paper. First and foremost, medical and recreational use of cannabis are not the same and their effects on cognition should not be assumed to be equivalent. Adding to this variability are the different constituents of cannabis studied, including whole plant cannabis and isolated compounds.

So much this. You need three way split studies (And perhaps different category naming).

- +50 year varieties of cannabis

- medical cannabis (Higher CBD, lower THC)

- Modern dispensary cannabis (high THC)

We keep selling the idea that bud is natural but ask anyone older than 60 who smokes and they will tell you 'modern' cannabis is absolutely wild compared with what existed a few decades ago.

Anecdata I personally know someone in their early 20 who experienced a major psychotic event following regular heavy use of cannabis.

The mental health and neural maturation of 13 to 25 yr old while consuming cannabis is something that also needs very urgent studying.

Medical cannabis doesn’t mean higher CBD lower THC at all as a blanket rule. It all depends what it’s intended to treat. For ongoing complications relating to a SCI for instance, they prescribe a high THC low CBD offering as higher THC is shown to be more effective for what they are trying to impact.

Yeah, they really don't know what they are talking about it seems. High CBD strains are relatively new to the scene, at least in popular adoption. Medical cannabis has been around since the 90's, and it was mostly potent strains that were preferred and shared among cardholders.

High CBD strains may be helpful for anxiety in some people, and are amazing for epileptic seizures. However, medical cannabis is prescribed for many other conditions as well. The pain relieving effects of cannabis are multifaceted, but generally speaking, strains with a higher ration of THC:CBD are going to perform better here (that doesn't at all mean higher THC = more pain relief, though).

You are correct. Again comes back to the need for better naming, I meant variants intended for seizure control in Epilepsy.

That makes sense. I only added my experience because I must admit that as a new patient, I went in asking for a "High CBD/low THC" option because I was under the impression early on that CBD was the more important therapeutic component and I didn't "want to be high" but was sadly informed that for pain, that was not particularly an option, which was very much new to me to learn.

I assume SCI == Spinal Cord Injury

> We keep selling the idea that bud is natural but ask anyone older than 60 who smokes and they will tell you 'modern' cannabis is absolutely wild compared with what existed a few decades ago.

To be fair, this is true of all drugs across the board, most notably alcohol.

As a daily weed smoker, over 60, who's not a fan of alcohol, I still have to disagree with this.

The strain selection that's gone on since cannabis was legalized has led to massively more potent strains.

But alcohol products, measured in "proof" equal to 2x the percentage of alcohol in the product, has been stable since before my lifetime.

Alcohol hasn't changed it's potency at all.

However to support your point (maybe), then and now, alcohol causes MUCH more social and medical harm than cannabis.

I should be more clear, I mostly mean alcohol in the time since the industrial revolution, after breakthroughs were made in the yeast technology. Prior to the developments, there was a limit to how potent we could brew alcohol before it poisoned the yeast. Although, IPAs are one example of alcohol potency increasing over the last few decades.

Perhaps the better comparison to cannabis is nicotine, which has also exploded in potency over the last 50 years. Anecdotally, this trend seems to be ingrained in human nature. We like are drugs and we like them as strong as we can make them.

We’ve had liquor for nearly as long as we’ve had alcohol. How has the potency of alcohol products increased? Yes there are stronger IPAs but they’re a small minority of alcohol products who are still well below the alcohol percentages of liquor or wine.

Also I don’t see how nicotine product potency has increased either. There’s just salt nicotine vapes now and they often still pale in comparison to strong tobacco in terms of nicotine concentration. And trust me the tobacco are ancestors had was just as strong if not stronger as what we have. We figured out selective breeding of plants a long time ago and tobacco has been openly grown for centuries.

I am not an "older person" and I was smoking bud a few decades ago, thank you very much. Some of the stuff I got back then was categorically better than a great deal of the dispensary bud found today. Some of the cannabis cup winning strains from the mid 90's to mid 2000's would beat the pants off of the vast majority of mega-THC, mass produced strains sold in your average pot shop in terms of pleasant qualitative effects. It's wonderful to be able to take a few hits and hit the perfect high.. you smoke less bud, experience more of the pleasant effects with less of the mind-numbing, paranoia, and other unpleasant side-effects. In the 70's (and still today with trash-tier cannabis) people had to smoke tons to get any effect. I have done this with Mexican brick weed (purchased in Mexico). It is just straight up an inferior experience, there is nothing more safe or beneficial to smoking a butt load of crappy weed in order to get high.

Also, it's kind of a myth that cannabis was terrible back in the 70's. A lot of it was, don't get me wrong. But selective breeding and sophisticated indoor growing techniques were developing at that time, so it was possible to get pretty damn good bud if you happened to know the right people. There is still plenty of outdoor 'Mexican brick weed' going around these days just like it was back in the 70's, and it's pure trash. And there is plenty of mediocre bud masquerading as "top shelf" going around today (including strains in dispensaries advertising astronomical and dubious THC percentages). As ever it takes a lot of time, expertise, equipment, and capital to produce truly great bud.

Now if you start talking about distillates and concentrates, that is one area in which I agree there is a notable difference in usage patterns and negative effects. It's kind of comparable to turning cocaine into free-base IMO.

>I personally know someone in their early 20 who experienced a major psychotic event following regular heavy use of cannabis

This is the classic timeframe for psychosis to develop. Despite millions of gov dollars spent trying to prove a connection, there is no evidence that cannabis causes psychosis:

Cannabis and Psychosis: a Critical Overview of the Relationship

https://pubmed.ncbi.nlm.nih.gov/26781550/

>Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis.

I don't use at all anymore, btw, so I'm definitely not a cannabis evangelist or any such. Just throwing in my two cents.

A long time ago, I smoked the shit out of some weed, for the first time in nearly a decade. I was so high, I literally couldn’t form a sentence if I wanted to. I couldn’t even move coherently. My friends took me to the emergency room and just left me there. I didn’t get in any trouble and didn’t mention weed at all. They classified it as a “psychotic break” or “psychosis”. It took me awhile to be able to speak properly and come down from the high (days!). I basically didn’t take what the docs prescribed since I knew that I was just so ridiculously high.

So, I can see the link. If you happen to get high enough, your brain just fails to work properly. Apparently this shows up as a medical condition. I recovered mostly fine. I still fail to say sentences properly, from time to time, since then.

The link between cannabis use and psychosis is very real, although it's less clear if cannabis causes the psychosis. Other people have come to different conclusions than the paper you linked.

At this point there it's hard to be sure one way or the other, but all things considered I feel there's enough to warrant some caution (also wrt. dependency and some other issues).

Correlation is not causation. There are plenty of other drugs (especially alcohol) used for self-medication that are also linked to psychoses, as well as non-drug behviours that are strongly correlated to psychoses. The immediate jump to causation is mostly politically-based and not scientifically-based.

> Correlation is not causation.

Yes, I believe I said this: "it's less clear if cannabis causes the psychosis". But thank you for your platitude.

The only answer which can be given with any certainty at this point is "we don't know", which may optionally be followed by "but I think that [..]". There is no "immediate jump" to causation; the only such jump I see here is dismissing things out of hand on account of allegedly being "politically-based".

> The only answer which can be given with any certainty at this point is "we don't know"

It might be a little more convincing if you shared whatever studies you're referencing to form this opinion, because while I don't have access to the paper linked above the abstract pretty definitively seems to be saying that we do know with some certainty:

> Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis.

>Future research studies that focus exclusively on the cannabis-psychosis association will therefore be of little value in our quest to better understand psychosis and how and why it occurs.

The full text is on Sci-Hub; I won't link to it here directly (I'm not sure if it's allowed?) but it's the first result in popular search engines for me.

Wikipedia has a decent overview of the available literature; when I looked at it last year I found it fairly comprehensive and balanced: https://en.wikipedia.org/wiki/Long-term_effects_of_cannabis#...

When you say weed was "better" in the mid 90's to mid 2000's - what do you mean? Back then I used to smoke an embarrassing amount every single day and loved it, pure bliss.

Over the years I've become less tolerant to it, it just makes me anxious and uncomfortably high.

So weed was definitely "better" back then, I just wonder what it was due to. Less THC, "better" psychoactive properties ... ?

Strangely enough the nicest highs I got were from brownies I made myself using only the leaves of the plants that were left over after harvest.

Exactly. It's only "natural" if you think dogs, cabbage and corn are natural. I think that's besides the point though. It's fallacious thinking. Wild tobacco is not what you want.

Not that any tibacco is, but you get the point.

Did the person recover from the event? I'm genuinely interested. I knew someone who seemed to have suffered something catastrophic from regualy ecstasy use. (this was twenty years ago, I haven't seen him since).

Personally I think weed is the most underestimated of all drugs. I smoked it for a while when I was a teenager and I think it left permanent bad effects. But I can never be sure.

What permanent bad effect do you think it has left? I do wonder about this too.

I binge drank between 14-16 years old, started smoking weed around the same time - and smoked daily from 20-25. After that I did a short bout of therapy and walked away from it. I'm now 40 and I do often wonder what damage might have been done.

If I'd have to guess how damage could materialise i'd point to the fact that my thinking was polarised for a long time and I had trouble controlling my emotions.

But those traits could easily be attributed to verbal aggression and a lack of trust and empathy in my childhood - which most likely contributed to the substance abuse in the first place (1) Or it could even just be attributed to the male brain taking a little more time to mature.

(1) https://www.theguardian.com/society/2023/oct/02/shouting-at-...

I skateboarded, drank and smoked with this guy when I was about 15/16 (he was just part of our little group that skated etc, not a close friend, more just someone I knew). He was really out going, funny, confident. Whatever happened I didn't see him for another five years or so. Then at about 21/22 years old, me and another mate met him randomly on the bus... Right away it was obvious that something had gone badly wrong for him. He seemed jittery and withdrawn. We all laughed at a joke together, ten minutes later he asked if we'd been laughing at him, it was so surprising. He explained he was no good at doing jobs and had failed at chefing. He also explained he'd been living in a house were they were they had been doing Es everyday (he'd moved out and stopped that). Some of his house mates I knew of vaguely, I knew them mostly as dodgy bastards that should be avoided at all costs.

Anyway he seemed to be a wreck of a person. Judging the character change I doubt it wasn't permanent damage, but I'm no expert.

Bizarrely this encounter was 20 years ago, and I remember it clearly because it was so utterly shocking to me.

Thanks for the link by the way. Ever since my daughter was born I've been stopping my wife from shouting at her or labelling her something negative, because I know all too well what it did to me (it was totally minor for me, but it's there). My wife has finally accepted this and it's stopped. Hrm, one positive impact I've had on the world I guess :)

Anecdotally have definitely known some heavy users of weed that noticeably experienced cognitive declines from their late teens / early 20s to their late 30s. They are not as sharp as they used to be and are burn outs to some extent. I don't think it's good for you long term. That being said, I still think it should be legal, but it should be known up front that this is what you're buying into as a habitual long term user.

Maybe not everyone is affected by weed in the same way, but even if it's a 10% chance it should be disclosed and known up front.

Personally I know people in a similar situation who kept heavy usage into their 40s and their memory is amazingly better than anyone and keeps getting better. They can tell you what happened on a certain day or remember a long number instantly. Very heavy usage but sticks to the same strain might be the key difference.

Anecdotally I'm finding my cognition has certainly improved after cessation of my heavy use, emotionally I'm also better balanced. Physical exercise seems to be the best thing for my health these days.

Ditto here, and matches the experience of many close friends and even colleagues. The emotional side of things is especially germane, I was definitely using mj to avoid facing up to some emotional difficulties.

It might sound a bit arcane, but I attribute a lot of it to REM sleep. When I quit, I had crazy dreams every night, often nightmares. But frankly, I had dug myself into a pretty deep hole in the real world. These nightmares and unpleasant dreams became much less frequent over time, and I still dream almost every night. When I was smoking every day, I didn’t notice this. I don’t notice that was waking up foggy, it was nothing compared to a hangover or a night with little sleep. But now it’s clear. I feel like I have an entire dimension of sharpness and control I was missing and I’m grateful for that.

Can confirm that part about sleep, dreams simply go away or at least I never recall having any. But good 8 hours uninterrupted still feel great.

Overall depends what your goals are, not everybody constantly strives to be at their sharpest point, a bit of chill isn't bad from time to time. I think the biggest problem with MJ is that for most folks the best setup would be consuming from time to time, ie 1x a week. But its easy to slip into more frequent usage, where drawbacks become bigger and benefits smaller.

I think weed suppresses dreaming (or at least, the memory of having dreamed). When I quit, I definitely get vivid dreams for a week or so.

This is exactly my experience. Weed steals my dreams. I don't mind this short term: I'm going through an overlong emotional event, and with frequent insomnia, weed takes away the anxiety of anticipating the fatigue the following day.

Oh definitely, MJ suppressing REM sleep has been studied and confirmed now.

Similar experience, good job on the change

It could be that memory improves, but the few long time users that I have known got serious problems when doing mentally heavy task such as arithmetic, for instance. All of them suspected it was due to the long term cannabis use.

were you stoned when you wrote this

You seem like a good candidate to test my observations.

Let's find out more about you. How is your memory? What is your age? What does your history and current usage look like?

i forget

Definitely sounds like what someone stoned would write! It helps my memory!! I swear!

Brabel your understanding of Rust Hashmaps is lacking. How is your memory, what is your age and usage history?

In my personal experience, I can't handle weed. It makes me paranoid. I tried a weekish ago to smoke a bit with some friends and while being high I remembered why I stopped years ago. My mind simply doesn't manage it very well. It makes me feel anxious and can't control negative thoughts (guilt, shame, mistakes etc not related with the action of consumption itself). I think we should avoid to fall into the "it's just a natural plant" fallacy I've personally heard many times.

Edit: Why the downvotes? I just mentioned a explicitly stated personal take related to the topic...

> We conducted a comprehensive systematic search of the recent literature on cognitive outcomes associated with cannabis use and cannabinoids in adults age 50 and older. Although there is evidence of modest negative effects on cognition in this population, larger controlled trials using validated outcome measures are greatly needed to better understand the role of cannabinoids in cognitive aging, as small sample sizes and variability in study designs limit our ability to draw definitive conclusions at this time.

>Although variability in the cannabis products used, outcomes assessed, and study quality limits the conclusions that can be made, modest reductions in cognitive performance were generally detected with higher doses and heavier lifetime use.

>However, larger methodologically rigorous trials and longitudinal studies that assess cognition prior to the initiation of cannabis use are greatly needed to infer a causal relationship. This need is highlighted by the fact that many negative effects on cognition that were reported by studies in this review decreased after adjusting for confounding variables (e.g., differences in premorbid IQ for users and nonusers).

So heavy lifetime use and high doses may case modest cognitive impairment in older adults... or it is pure correlation, and perhaps older adults seeking strong relief have other things going on prior to heavy cannabis use that also cause cognitive impairment.

'Modest' just means you don't require a helper to perform every day tasks. It can be be very debilitating, but isn't 'Major' until you can't perform every day activities on your own. For further context, Trisomy 21 (Down Syndrome) is characterized as 'mild to moderate'.

    Modest: No interference with independence in everyday activities, although these activities may require more time and effort, accommodation, or compensatory strategies

Greater context, which doesn't seem to line up well with your assertion here:

> ...that higher doses and heavier use of cannabis are associated with modest negative effects. These findings are consistent with other systematic reviews and meta-analyses showing similar small adverse effects on cognition in younger populations. With that said, there was also evidence of modest improvements in subjective cognition on patient-reported outcome measures, particularly for medical cannabis users.

Because of a subjective improvement? I don't follow what you mean. People believe they are subjectively driving fine while hitting every mailbox due to being drunk.

I do not work in academia, but to me the summary of the paper sounds completely useless. Shouldn't they at least have have mentioned the core finding first in the summary before saying that more studies are necessary?

Unless the core finding was that funding was running out and they need more money.

Published in 2019

lol breaking news

No mention of combined use with tobacco?

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