Marijuana may stave off Alzheimer's - U.S. study

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Marijuana may stave off Alzheimer's - U.S. study

Thu Oct 5, 2006 9:17 PM BST

By Andy Sullivan

WASHINGTON (Reuters) - Good news for ageing hippies: smoking pot may stave off Alzheimer's disease.

New research shows that the active ingredient in marijuana may prevent the progression of the disease by preserving levels of an important neurotransmitter that allows the brain to function.

Researchers at the Scripps Research Institute in California found that marijuana's active ingredient, delta-9-tetrahydrocannabinol, or THC, can prevent the neurotransmitter acetylcholine from breaking down more effectively than commercially marketed drugs.

THC is also more effective at blocking clumps of protein that can inhibit memory and cognition in Alzheimer's patients, the researchers reported in the journal Molecular Pharmaceutics.

The researchers said their discovery could lead to more effective drug treatment for Alzheimer's, the leading cause of dementia among the elderly.

Those afflicted with Alzheimer's suffer from memory loss, impaired decision-making, and diminished language and movement skills. The ultimate cause of the disease is unknown, though it is believed to be hereditary.

Marijuana is used to relieve glaucoma and can help reduce side effects from cancer and AIDS treatment.

Possessing marijuana for recreational use is illegal in many parts of the world, including the United States, though some states allow possession for medical purposes.



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Researchers at the Scripps Research Institute in California found that marijuana's active ingredient, delta-9-tetrahydrocannabinol, or THC, can prevent the neurotransmitter acetylcholine from breaking down more effectively than commercially marketed drugs.

THC is also more effective at blocking clumps of protein that can inhibit memory and cognition in Alzheimer's patients, the researchers reported in the journal Molecular Pharmaceutics.

So THC is a superior acetylcholinesterase inhibitor and effectively inhibits amyloid beta plaque formation? I didn't see that one coming! Still, practical observation indicates the net effect of THC on cognition is undoubtedly negative -- I don't think that can be disputed.

Ironic that a substance best known for impairment of memory (short-term anyway) could potentially save your memory in the long run isn't it?

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THC inhibits short term memory not long term particularly. AS the two operate with slightly different mechanism this may be important to fine tune our understanding of memory as well.

In Alzheimer's the destruction is of long term memory more than short. People can have a conversation and then forget it the next day or forget their children but they tend to be cogent in terms of short term memory as they can conduct a conversation depending on what stage they are in. What is also interesting is they forget how to talk late in the deterioration but only forget specific less used words along the way. Does language blend long and short term memory for recall of complex vocabulary versus daily use?

Cognitive psych would support that hypothesis.


If THC is helping long term memory I wonder about the mechanism for that in terms of the biochemistry of memory. Is it reinforcing long term memory at the expense of short term and that is how it inhibits memory?

The short term impairment of memory is just while high, isn't it? I don't see how anyone can say about pot that the overall effect on cognition is negative. If those alzhiemers patients had just smoked a doobie on a regular basis, they wouldn't have that problem.

It's funny how the people who defend alcohol against all the evidence also attack pot. The main problem with cannabis is the screwed up legal system.

The short term impairment of memory is just while high, isn't it?

No, it impairs short-term memory in users throughout periods of regular use and for some length of time afterward, not only during the actual high.

I think everyone will understand if I don't take up smoking cannabis any time soon. Further research into this might yield promising results though

No, it impairs short-term memory in users throughout periods of regular use and for some length of time afterward, not only during the actual high.

For who?

for me:

I was a regular smoker until 8 weeks ago when I quit completely, but I only noticed short term memory loss while high or late in the day after smoking multiple times earlier in the day. I doubt marijuana had any detrimental effects on long term memory because I did great in school then and I remember as much as anyone else (if not more) of previous classes today. Pot made me unproductive, but it never directly hindered my intelligence- even taking into account the temporary drop in short term memory (different strengths are offered by that weakness).

I was a stoner untill about 3 years ago. I lost my job and had to stop because I never knew if I would be tested for a new job. I have not smoked weed since then and did not notice a decrease in my memory when I started or stopped. I DID notice a HUGE difference in my motivation during that time. Marijuana seemed to increase my ability to concentrate on simple tasks but detracted from my ability to look at the big picture.
( I feel preachy now)
I still have no problems with recreational drugs, but I feel that people need a more honest education about them.
YES!, drugs are/can be fun but they should be treated with respect.
I have only habitually used marijuana and tobacco. I have experimented with LSD, ecstasy, opium, cocain, valium, xanax, alchohol and "shrooms".

Remeber that marijuana induces neurogenesis after repeated use in the hippocampus which has a large part in long term memory

http://www.scienceda...40513010413.htm

http://www.jci.org/c...journalcode=jci

I find it very odd that cannibis works in this way. From personal expereince it is very hard to recall memories and learned material that was created while high unless in the same state as in which the memories were made. So you almost have to relearn things after smoking longterm. I would think this would cause lower stimualtion of important neural pathways causing cognitive decline.When i smoke (which i dont anymore) i get a flush of memories from all my high experiencese along with a very different personality. Maybe smoking for a long time makes stronger connections to higher cognitive processes that ultimatley makes you "sharper"

Those afflicted with Alzheimer's suffer from memory loss, impaired decision-making, and diminished language and movement skills. The ultimate cause of the disease is unknown, though it is believed to be hereditary.

Thats funny it sounds like someone whos high [lol]

So i guess you can have Alzheimers like symptoms your whole life to not have it when your about to die. I dont know about that trade off. Oh and then die from lung cancer [thumb]

LOL. I'd like to see one of these studies on the prime time news. I doubt that will ever happen though.

I have friend who uses pot daily and has been doing so for many years. He's very intelligent (IQ around 140), but he certainly has problems with his personality which I think is due to cannabis, especially in the motivation department and also being antisocial.
There's also some people out there with certain genes which induce psychosis in the vulnerable individuals who smkoe pot, and many more people who get all sorts of other psychological problems from pot use.
Marijuana certainly has been bashed too much by the general medical community, because there are many compounds that offer benefits for treating a number of conditions. When it comes to pot, you just have to be reasonable with its use and understand how it really affects your cognition and then decide if the effects are what you're looking for or not.

No, it impairs short-term memory in users throughout periods of regular use and for some length of time afterward, not only during the actual high.

For who?

For heavy users at least. These two studies seem to disagree as to whether the cognitive deficits are reversible or cumulative with years of use, but they both demonstrate that negative effects persist for some length of time after use is discontinued.

Arch Gen Psychiatry. 2001 Oct;58(10):909-15. 

    Neuropsychological performance in long-term cannabis users.

    Pope HG Jr, Gruber AJ, Hudson JI, Huestis MA, Yurgelun-Todd D.

    McLean Hospital, Harvard Medical School, 115 Mill St, Belmont, MA 02478, USA.

    BACKGROUND: Although cannabis is the most widely used illicit drug in the United States, its long-term cognitive effects remain inadequately studied. METHODS: We recruited individuals aged 30 to 55 years in 3 groups: (1) 63 current heavy users who had smoked cannabis at least 5000 times in their lives and who were smoking daily at study entry; (2) 45 former heavy users who had also smoked at least 5000 times but fewer than 12 times in the last 3 months; and (3) 72 control subjects who had smoked no more than 50 times in their lives. Subjects underwent a 28-day washout from cannabis use, monitored by observed urine samples. On days 0, 1, 7, and 28, we administered a neuropsychological test battery to assess general intellectual function, abstraction ability, sustained attention, verbal fluency, and ability to learn and recall new verbal and visuospatial information. Test results were analyzed by repeated-measures regression analysis, adjusting for potentially confounding variables. RESULTS: At days 0, 1, and 7, current heavy users scored significantly below control subjects on recall of word lists, and this deficit was associated with users' urinary 11-nor-9-carboxy-Delta9-tetrahydrocannabinol concentrations at study entry. By day 28, however, there were virtually no significant differences among the groups on any of the test results, and no significant associations between cumulative lifetime cannabis use and test scores. CONCLUSION: Some cognitive deficits appear detectable at least 7 days after heavy cannabis use but appear reversible and related to recent cannabis exposure rather than irreversible and related to cumulative lifetime use.

    PMID: 11576028 [PubMed - indexed for MEDLINE]

JAMA. 2002 Mar 6;287(9):1123-31. 

    Cognitive functioning of long-term heavy cannabis users seeking treatment.

    Solowij N, Stephens RS, Roffman RA, Babor T, Kadden R, Miller M, Christiansen K, McRee B, Vendetti J; Marijuana Treatment Project Research Group.

    National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW 2052, Australia. n.solowij@unsw.edu.au

    CONTEXT: Cognitive impairments are associated with long-term cannabis use, but the parameters of use that contribute to impairments and the nature and endurance of cognitive dysfunction remain uncertain. OBJECTIVE: To examine the effects of duration of cannabis use on specific areas of cognitive functioning among users seeking treatment for cannabis dependence. DESIGN, SETTING, AND PARTICIPANTS: Multisite retrospective cross-sectional neuropsychological study conducted in the United States (Seattle, Wash; Farmington, Conn; and Miami, Fla) between 1997 and 2000 among 102 near-daily cannabis users (51 long-term users: mean, 23.9 years of use; 51 shorter-term users: mean, 10.2 years of use) compared with 33 nonuser controls. MAIN OUTCOME MEASURES: Measures from 9 standard neuropsychological tests that assessed attention, memory, and executive functioning, and were administered prior to entry to a treatment program and following a median 17-hour abstinence. RESULTS: Long-term cannabis users performed significantly less well than shorter-term users and controls on tests of memory and attention. On the Rey Auditory Verbal Learning Test, long-term users recalled significantly fewer words than either shorter-term users (P =.001) or controls (P =.005); there was no difference between shorter-term users and controls. Long-term users showed impaired learning (P =.007), retention (P =.003), and retrieval (P =.002) compared with controls. Both user groups performed poorly on a time estimation task (P<.001 vs controls). Performance measures often correlated significantly with the duration of cannabis use, being worse with increasing years of use, but were unrelated to withdrawal symptoms and persisted after controlling for recent cannabis use and other drug use. CONCLUSIONS: These results confirm that long-term heavy cannabis users show impairments in memory and attention that endure beyond the period of intoxication and worsen with increasing years of regular cannabis use.

    PMID: 11879109 [PubMed - indexed for MEDLINE]

Edited by FunkOdyssey, 06 October 2006 - 02:29 PM.

There is a brief cognitive impairment for a while after using. There is no evidence at all to suggest long term impairment in fact, evidence shows the opposite. Alzheimers is kind of long term, from what I've heard. I'd rather not get it. Feel free to stick with your alcohol.

LOL. I'd like to see one of these studies on the prime time news. I doubt that will ever happen though.

O RLY?

http://www.cnn.com/2...reut/index.html

uhmm....

what about one's lungs..

unless all your pot is brownies..

The mechanism by which marijuana is meant to possibly reduce Alzheimers disease is a decrease in the breakdown of secreted acetylcholine (ACh), allowing this neurotransmitter to "hang around" for a longer period. But marijuana also inhibits ACh release from cholinergic hippocampal neurons (yes, those neurons that are involved in memory formation) leading to a decrease in ACh-mediated memory encoding.

The best cognitive enhancer for a marijuana user is to stop using.

The latest review on memory and cannabis use:

Prometheus: that is one of the most amazing articles ive read in a long time. Not only did it tell you about marijuana's effects on memory; It also went into great detail on how the whole memory system itself actually works! Thank you for this knowledge

uhmm....

what about one's lungs..

unless all your pot is brownies..

Vaporizer......although a quality one is expensive.

[quote]THC is also more effective at blocking clumps of protein that can inhibit memory and cognition in Alzheimer's patients, the researchers reported in the journal Molecular Pharmaceutics.[/quote]

The significance of this study -- which appears to be overlooked by many -- is that THC might be effective at breaking down beta-amyloid plaques and neurofibrillary tangles.

http://www.ahaf.org/...loidPlaques.htm



[quote name='http://www.ahaf.org/alzdis/about/AmyloidPlaques.htm']The formation of amyloid plaques and neurofibrillary tangles are thought to contribute to the degradation of the neurons (nerve cells) in the brain and the subsequent symptoms of Alzheimer's disease.

AMYLOID PLAQUES

One of the hallmarks of Alzheimer's disease is the accumulation of amyloid plaques between nerve cells (neurons) in the brain. Amyloid is a general term for protein fragments that the body produces normally. Beta-amyloid is a fragment of a protein that is snipped from another protein called amyloid precursor protein (APP). In a healthy brain, these protein fragments would be broken down and eliminated. In Alzheimer's disease, the fragments accumulate to form hard, insoluble plaques.

NEUROFIBRILLARY TANGLES

Neurofibrillary tangles consist of insoluble twisted fibers that are found inside of the brain's cells. They primarily consist of a protein called tau, which forms part of a structure called a microtubule. The microtubule helps transport nutrients and other important substances from one part of the nerve cell to another. In Alzheimer's disease, however, the tau protein is abnormal and the microtubule structures collapse.[/quote]

Researchers at the Scripps Research Institute in California found that marijuana's active ingredient, delta-9-tetrahydrocannabinol, or THC, can prevent the neurotransmitter acetylcholine from breaking down more effectively than commercially marketed drugs.

but according to Eric R. Braverman, M.D. marijuana mimics the effects of GABA, arguably an equally important neurotransmitter, and with regular use causes our brains to reduce the amount of GABA produced creating a vicious cycle

http://thescienceexp...alzheimers-risk
 

Marijuana Users Have Low Blood Flow to the Brain, Suggesting Higher Alzheimer's Risk

November 28, 2016 | Kelly Tatera

 

 

it's worth noting too much acetylcholine also potentially has its drawbacks.

but I think the glutamate and dopamine depletion are responsible for most of the deleterious effects, which are typically so severe that heavy use can hardly be recommended in the elderly

interesting article on alzheimer and marijuana use association. its kind of strange for me though since i have never seen a single report of someone with current alzheimer's having reported or someone reliable of them reporting a heavy use of marijuana in their lifetime. i find this quite shocking because i personally dealt with people having the condition and knowing their lifestyles, most did not have the typical alcohol, marijuana use to begin with

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i personally dealt with people having the condition and knowing their lifestyles, most did not have the typical alcohol, marijuana use to begin with

Your limited experience may not be representative of the whole.  last I checked^[1], alcoholism had no influence on the risk of later developing dementia.  while drugs will cause secondary impairments, their mechanism are quite independent of beta amyloids and tau aggregates.  weed may even reduce their formation but not to a clinically relevant degree.  to confirm the lack of effect in either direction, it's going to take time.  how many stoners are coming of age? anyone in their 70s now would be in their 20s in the 1960s, and this was just as the hippie movement was starting to gain weight.  we have to wait a couple generations for the guniea pigs to come due