Smoking High-Strength Cannabis May Damage Nerve Fibres In Brain

[zachw]

 

High-strength cannabis may damage nerve fibres that handle the flow of messages across the two halves of the brain, scientists claim. Brain scans of people who regularly smoked strong skunk-like cannabis revealed subtle differences in the white matter that connects the left and right hemispheres and carries signals from one side of the brain to the other.

 

The changes were not seen in those who never used cannabis or smoked only the less potent forms of the drug, the researchers found.

 

The study is thought to be the first to look at the effects of cannabis potency on brain structure, and suggests that greater use of skunk may cause more damage to the corpus callosum, making communications across the brain’s hemispheres less efficient.

 

Paola Dazzan, a neurobiologist at the Institute of Psychiatry at King’s College London, said the effects appeared to be linked to the level of active ingredient, tetrahydrocannabinol (THC), in cannabis. While traditional forms of cannabis contain 2 to 4 % THC, the more potent varieties (of which there are about 100), can contain 10 to 14% THC, according to the DrugScope charity.

 

“If you look at the corpus callosum, what we’re seeing is a significant difference in the white matter between those who use high potency cannabis and those who never use the drug, or use the low-potency drug,” said Dazzan. The corpus callosum is rich in cannabinoid receptors, on which the THC chemical acts.

 

“The difference is there whether you have psychosis or not, and we think this is strictly related to the potency of the cannabis,” she added. Details of the study are reported in the journal Psychological Medicine.

 

The researchers used two scanning techniques, magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI), to examine the corpus callosum, the largest region of white matter, in the brains of 56 patients who had reported a first episode of psychosis, and 43 healthy volunteers from the local community.

 

The scans found that daily users of high-potency cannabis had a slightly greater – by about 2% – “mean diffusivity” in the corpus callosum. “That reflects a problem in the white matter that ultimately makes it less efficient,” Dazzan told the Guardian. “We don’t know exactly what it means for the person, but it suggests there is less efficient transfer of information.”

 

The study cannot confirm that high levels of THC in cannabis cause changes to white matter. As Dazzan notes, it is may be that people with damaged white matter are more likely to smoke skunk in the first place.

 

“It is possible that these people already have a different brain and they are more likely to use cannabis. But what we can say is if it’s high potency, and if you smoke frequently, your brain is different from the brain of someone who smokes normal cannabis, and from someone who doesn’t smoke cannabis at all,” she said.

 

But even with the uncertainty over cause and effect, she urged users and public health workers to change how they think about cannabis use. “When it comes to alcohol, we are used to thinking about how much people drink, and whether they are drinking wine, beer, or whisky. We should think of cannabis in a similar way, in terms of THC and the different contents cannabis can have, and potentially the effects on health will be different,” she said.

 

“As we have suggested previously, when assessing cannabis use, it is extremely important to gather information on how often and what type of cannabis is being used. These details can help quantify the risk of mental health problems and increase awareness of the type of damage these substances can do to the brain,” she added.

 

In February, Dazzan and others at the Institute of Psychiatry reported that the ready availability of skunk in south London might be behind a rise in the proportion of new cases of psychosis being attributed to cannabis.

Full article here.

[t-pain]

the UK is going full on looney toons with this "skunk" propaganda

[Willy]

"traditional forms of cannabis contain 2 to 4 % THC,"   woah lol were do they get that number from,, wild dirt weed outta indianna... If I dont get at least 16% I dump it in the burn barrel or the hole in the ground to rot.. I dont believe that would ever have been a average, even back in the "" days of our fathers weed"" hell i am the father,, it was as good as now, and some even better.. of course there is MORE higher quality now but its just more frequent. not the killer that came thru in season.. LOL 

[Wild Bill]

When I saw "skunk like" I knew it came from England. Skunk is the new catch phrase for the fear mongers over there. It's so much stronger than what they're used to it must have come straight from Satan. Not like regular marijuana, it will kill infants if they so much as glance at it.

[GrowGoddess]

I hate seeing studies like this. So deceiving and inadequate. They relate smoke to all THC. What, are their brains on prescription drugs or something?

 

Smoking, vaping, and eating cannabis are three different things. Maybe they should first decipher the differences between each method. I am sure they will receive different results. They will probably all be medicinally positive results, but they would not want to share that information with the masses.

 

I stop reading studies like this at the point where they relate all marijuana use to being smoked. If they are testing for smoking, then they are only testing for negative results. We all know that they manipulate the test results to get the outcome they desire.

 

There are a lot of other factors. Did the product have mold? Did the people who smoked, smoke pesticide soaked product? Pesticides cause all kinds of problems.

 

Either way, if their studies are correct, I may not have a brain!!!

 

I must say this, at least I was smart enough to NOT go shopping on Black Friday! Just staying home and smoking a fatty. LOL!

[outsideinthecold]

Apparently seven-thousand years of happy human history breeds hysterical homilies.

[Kingdiamond]

Slanderous propaganda that shouldn't be on our boards pure fabrication  article.

[solabeirtan]

This might be the original article that the Guardian is referencing at Kings College.  This is from Cambridge U Psychology Journal and titled "Examining the profile of high-potency cannabis and its association with severity of cannabis dependence" and does seem to be objectively based.  
 
 
So far this is the most disturbing item I discovered: "Younger people were especially vulnerable, displaying a stronger relationship between extent of skunk use and severity of dependence. This is in agreement with observations that more under 18's seek treatment for cannabis than all adults combined, unlike any other drug (NDTMS, 2014, 2015). Young people in our sample were also exposed to skunk from an earlier age; older adults tried resin first and had not tried skunk until an average of 2.42 years later. Given that these changes in the illicit market may have increased rates of cannabis dependence in the UK, it will be important to evaluate the impact of careful regulation of cannabis potency (e.g. as planned in Uruguay) and other legislative changes (e.g. in the US) on cannabis dependence."


*edited to correct link

Edited November 27, 2015 by solabeirtan

[imiubu]

I hate seeing studies like this. So deceiving and inadequate. They relate smoke to all THC. What, are their brains on prescription drugs or something?

 

Smoking, vaping, and eating cannabis are three different things. Maybe they should first decipher the differences between each method. I am sure they will receive different results. They will probably all be medicinally positive results, but they would not want to share that information with the masses.

 

I stop reading studies like this at the point where they relate all marijuana use to being smoked. If they are testing for smoking, then they are only testing for negative results. We all know that they manipulate the test results to get the outcome they desire.

 

There are a lot of other factors. Did the product have mold? Did the people who smoked, smoke pesticide soaked product? Pesticides cause all kinds of problems.

 

Either way, if their studies are correct, I may not have a brain!!!

 

I must say this, at least I was smart enough to NOT go shopping on Black Friday! Just staying home and smoking a fatty. LOL!

 

 

 I stayed home also!  I'll wait for cyber Monday... forget going out in those crazy crowds... nothing I need that badly.

[AmishRnot4ganja]

For all the hoopla that this article attempts to generate, the really important fact that they so gently interjected is this: the detrimental effects that they go to great lengths to make appear to be earth shattering only affect 2% of all cannabis users. Come on! Give it up already! 98% of cannabis users will not experience these effects - even if they smoke "skunk" all day, everyday!

 

On a mundane side note, I can't wait for my new Lemon Skunk to be ready.

[Wild Bill]

These f'n buffoons think skunk is a separate substance altogether.

 

Skunk causes similar effects to cannabis, although they can come on more quickly and more strongly. Some of the side effects include: relaxation, alteration of time and perception, talkativeness, "the munchies", nervousness, anxiety and mild paranoia.

 

http://www.huffingtonpost.co.uk/2013/11/06/skunk-cannabis-top-10-fac_n_4226260.html

[t-pain]

full text of study here:

http://journals.cambridge.org/download.php?file=%2FPSM%2FS0033291715002342a.pdf&code=4e65ff6df3209680e051a6bcc1b17fc3

 

i knew it was a bad study from how poorly the abstract was written. but look at this

 

A total of 56 patients with first-episode psychosis (FEP)

were recruited from South East London (UK).

 

...

 

At the time of the

MRI, 48 patients were taking atypical antipsychotics,

five were taking typical antipsychotics and three

were antipsychotic naive.

its not a study on marijuana at all. its a study on how antipsychotics affect the brain. or a completely messed up sample bias. either way.

 

 

 

 

this is common amongst these "research studies" where they are looking for harms of cannabis.

 

common bias pattern in these unscientific propaganda pieces:

 

1. research focuses on young men only (no women?)

2. sample size is small, under 100

3. cannabis users have double the alcohol or tobacco use of the controls

[solabeirtan]

Good work T, I didn't have any luck finding the f thing.  Thanks.  You are partially correct that the study group is relatively small. The technology is quite advanced. However they admit to using ver 0.4.3 of the software (trackvis.org) used to create the images, that software is currently on ver 0.6. There is an interactive demo available on that site which demonstrates the complexity and relative difficulty in trying to do what they're doing.  

 

They have used two groups for their basis. One group are patients having had their first psychotic episode. They are on typical (thorazine) as well as atypical (experimental?) anti-psychotics but had not been on them a long time (little less than 4 mos, mean). That group consisted of 56 patients (25 females) with 37 of 56 cannabis users. The other group was without psychosis and had 43 individuals (21 were females) of which 22 of 43 used the herb. (pg4)

They claim there was no significant difference in alcohol use between groups. 

 

 However the variations described in tables (pgs 7, 8, 9) between the low and high potency are imho miniscule and therefore I believe they are reading a surprising amount into their conclusion. 

[zachw]

Thanks t-pain, for finding the original research. It's important to analyze scientific studies beyond the abstract that mass media likes to publicize.

 

Too often (like almost always!) the "pro-cannabis" world will have a knee jerk response to any research that points to deleterious effects of cannabis on health. Most common response is "poorly designed study" regardless of the individual's knowledge of scientific study methods & statistics. Other retorts include "1000s of years of cannabis use says otherwise" or "anti-cannabis propaganda" (Kingdiamond even said that this was "Slanderous propaganda that shouldn't be on our boards pure fabrication  article". SERIOUSLY, do you think that this study shouldn't even have been mentioned??). 

 

Here are some other techniques. Just say "correlation does not imply causation" and leave it at that. Or pick apart some factoid by the authors (I'd harp on the use of "hash-like" to mean "low potency" in the study.) Or use anecdotal evidence (which is not scientific AT ALL) such as "I know that I'm a safe driver while stoned" or "THC cured my cancer"..

 

I have not analyzed the study in depth and do have some issues with the methodology but regardless it does seem to support SOME research that suggests that brain changes do occur in users that start when they are very young and the brain is still developing (look up "synaptic pruning" and "myelination".)

 

OTOH, I am bothered that the authors did not even mention either the 2000 study by Block et al or the 2014 one by Weiland et al, neither of which showed morphological brain changes in marijuana users, even young ones.

 

I'll just end my rant with "interesting study. I hope that cannabis will be removed from schedule 1 so that lots more research can be done in the USA".

[t-pain]

"SERIOUSLY, do you think that this study shouldn't even have been mentioned??). "

 

 

yes, i agree with kingdiamond that this study, based on estimates and self-reported use, should not even be mentioned, unless it is put in context as being the propaganda that it is.

 

 

this study is flawed in many ways, i'll try to explain. i could be wrong.

 

the marijuana group that they are studying have all been diagnosed with the following:

Diagnosis by ICD-10, number

Schizophrenia 14

Acute psychotic disorder 12

Schizo-affective disorder 8

Unspecified non-organic psychosis 5

Bipolar affective disorder 10

Depressive episode with psychotic symptoms 7

this data is first-try theory stuff. maybe this study would be good, if and only if they can replicate it on people who havent been admitted to hospital and arent diagnosed with the above symptoms.

 

the study says as much

Alterations in the microstructural organization of the

CC and other WM structures have been reported in

patients with psychosis in vivo using diffusion tensor

imaging (DTI) (Brambilla et al. 2005; Kanaan et al.

2005; Shergill et al. 2007; Cheung et al. 2008;

Kyriakopoulos et al. 2008).

 

these alterations of the CC and WM could be "normal" for patients with psychosis. nothing to do with marijuana.

 

 

However, only three studies

have specifically evaluated diffusion microstructural

properties of WM in patients with psychosis who

were also cannabis users, with inconsistent findings

(Peters et al. 2009; Dekker et al. 2010; James et al.

2011).

 

the best kind of research, inconsistent research! send us more grant money so we can "prove" nothing.

 

 

 

also this:

Other drugs, n (%) e 22 (64.7) 12 (35.3) df=2, ? 2 =5.9, p=0.05

the marijuana group had 22 people who used other drugs, while the control group had 12 people who used other drugs.

so the study is trying to say that these other drugs we're going to ignore, and only focus on marijuana.

i'm not saying they need marijuana-only control group or anything, but its very obvious that they are ignoring which other drugs they are using. inhalents, those change brains because of oxygen depravation. wouldnt you control for inhalents?

 

 

btw, more about sample size...

No cannabis use 16 (32) 22 (55) df=2, ? 2 =5.6, p=0.06

the psychotic group has 16 people who have never used marijuana.

 

so now you are trying to base your "marijuana causes brain changes" on only 34~ peoples' scans. not 50~.

 

 

 

Here are some other techniques. Just say "correlation does not imply causation" and leave it at that. Or pick apart some factoid by the authors (I'd harp on the use of "hash-like" to mean "low potency" in the study.) Or use anecdotal evidence (which is not scientific AT ALL) such as "I know that I'm a safe driver while stoned" or "THC cured my cancer"..

 

anecdotal does not mean incorrect. so someone saying they are a safe driver can be a fact. or someone saying thc got rid of their cancer can also be a fact.

 

whats interesting is that this study RELIES on anecdotal evidence. they gave them a paper to fill out that explains how much people use , what quality they smoke (by guessing?).

from the pdf:

Assessment of cannabis use

A detailed history of illicit drug use (cannabis, stimu-

lants and any other recreational drug) was taken

using the Cannabis Experience Questionnaire modified

version (Di Forti et al. 2009). This allows a detailed as-

sessment of lifetime patterns of cannabis use, includ-

ing: frequency and duration of use, the specific type

of cannabis used and age at first use.

 

anecdotal evidence could also be wrong. but it is with gathering all of the anecdotal evidence together and then judging it do we see patterns.

 

 

I have not analyzed the study in depth and do have some issues with the methodology but regardless it does seem to support SOME research that suggests that brain changes do occur in users that start when they are very young and the brain is still developing (look up "synaptic pruning" and "myelination".)

 

sorry, I have analyzed this study and all of the other brain morphology studies and they prove nothing aside from the researchers having biased sample volunteers.

 

 

OTOH, I am bothered that the authors did not even mention either the 2000 study by Block et al or the 2014 one by Weiland et al, neither of which showed morphological brain changes in marijuana users, even young ones.

 

i am fully for more research, but i am also fully against uninformed people standing up for these lying propaganda studies and "giving the benefit of the doubt".

 

if you havent even read the thing, STFU.

 

look at the bunny muffin in this study:

 

 

 

 

Interestingly, the THC component of canna-

bis has been proposed to have a neurotoxic effect on the

brain (Gilman et al. 2014)

they quoted the study where the marijuana users had TWICE the amount of alcohol as the control.

look at it yourself: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3988409/table/T1/

 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3988409/

 

 

the only alcohol they mention in this study is this:

There was also no significant difference between

groups for alcohol use (x 2 =0.12, p=0.7) or alcohol in-

take in terms of units per week (x 2 =4.6, p=0.2).

but they dont provide the numbers so the p value is worthless.

 

 

These factors potentially affect all neu-

roimaging investigations and make it difficult to ex-

trapolate whether differences in findings are due to

sample characteristics or methods used.

pretty much sums up what i'm saying.

 

The lack

of objective measures of cannabis use is another im-

portant limitation. However, other studies that have

used self-report measures have also shown an associ-

ation with brain structural alterations (Yücel et al.

2008; Cousijn et al. 2012).

 

ok these two cites are:

yucel: http://truecompassion.org/PDFS/Health%20and%20Mental%20Health/Brain%20Regional%20Abnormalities%20Hippo%20Aust%20ArchGenPsych.pdf

 

double the tobacco use, more alcohol use.

 

 

i will look for the cousijn study later.

 

of course this study does not mention the study that contradicts it.

"Daily Marijuana Use Is Not Associated with Brain Morphometric Measures in Adolescents or Adults"

http://www.jneurosci.org/content/35/4/1505.full.pdf

(thats the study in 2014 you were talking about? i think)

 

 

 

its pretty simple if they want to replicate research like this. just do it on rats and show us the rat brains change size. whats difficult about that?

[outsideinthecold]

Somebody should do a brain scan on the researchers AND those who fund their grants.

[t-pain]

I should say I'm not attacking you Zach, I'm just angry at this poor research

[Restorium2]

I have been getting reports back from some patients that small amounts of ingested cannabis oil helps long term depression. It actually gives people their lives back after long periods of dis function and destructiveness. It's such an awesome thing that no bogus 'brainshinking' or 'nerve killing' study can overshadow the real results. And it not some 'special' kind of cannabis oil either. It's the kind of cannabis oil anyone could make. There's no special ratio of THC to CBD that only works. There's no 'special' tricks you have to pay for. It's just cannabis oil. A tiny bit in a gel cap.

How could anything be so simple? 

 

Just keep helping people and the word gets out.

 

No one believes these studies any more. They switcheroo the results like underwear depending on what they want to prove. 

 

It's really too bad they have fudged their reports over the years to the point of ruining the credibility of the whole study industry. 

[Restorium2]

I should say I'm not attacking you Zach, I'm just angry at this poor research

There are so many studies and statistics that have been purposefully skewed to reflect a 'different reality' it's very frustrating. 

[AmishRnot4ganja]

There are so many studies and statistics that have been purposefully skewed to reflect a 'different reality' it's very frustrating.

 

 

A little more objectivity would be most welcome in the Great Marijuana Debate.

[t-pain]

quick question: does anyone think this study proves that high thc causes brain damage while also proving that low thc does not cause any damage in your brain?

 

because thats what this study is saying. does anyone here agree with the conclusions of this study?

 

or does anyone agree that this theory could be possible?

 

the first comment i saw about this study was something like "if you smoke only a little high thc but a lot of low thc, wouldnt that be the same amount of thc in your blood? high thc is not any different than low thc. its the same thc molecule. kind of like 1 shot of vodka vs 2 beers, its the same amount of alcohol."

 

when the very foundation of the correlation (high thc bad vs low thc no problem) has not been tested or controlled and is being self-reported by newly-admitted hospital patients who have been recently diagnosed with psychotic disorders, it raises so many red flags for me.

[Wild Bill]

"traditional forms of cannabis contain 2 to 4 % THC,"   woah lol were do they get that number from 

This is from a country where the standard is "soapbar hash". It's a highly adulterated product containing,"Beeswax, turpentine, milk powder, ketamine, boot polish, henna, pine resin, aspirin, animal turds, ground coffee, barbiturates, glues and dyes plus carcinogenic solvents such as Toluene and Benzene".

 

This new "skunk" probably worries them because people actually get high on it. With soapbar they can point to genuine health concerns, they have to make them up with the dreaded skunk.

[zachw]

This is from a country where the standard is "soapbar hash". It's a highly adulterated product containing,"Beeswax, turpentine, milk powder, ketamine, boot polish, henna, pine resin, aspirin, animal turds, ground coffee, barbiturates, glues and dyes plus carcinogenic solvents such as Toluene and Benzene".

 

This new "skunk" probably worries them because people actually get high on it. With soapbar they can point to genuine health concerns, they have to make them up with the dreaded skunk.

 

Inneresting. Never heard of soapbar hash before. I was puzzled by the study's use of "hash-like" for "low-thc", but it now makes some sense.

[Wild Bill]

They're also spraying cannabis with fibre glass so it will sparkle! Here's a site that talks about it and tells you how they make soapbar.

 

http://www.ccguide.org/badsoap.php

[GregS]

2% is not statistically significant in any sense of the imagination.