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is cannabis neurotoxic ?

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markosheehan

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i have seen a lot of studies lately saying cannabis has morphological changes on brain structure . what could be the implications of these brain changes does anyone know?

http://onlinelibrary.wiley.com/doi/10.1111/pcn.12085/abstract


http://www.jneurosci.org/content/18/14/5322.full
this study says its neurotoxic

"The data reported in our study are consistent with this hypothesis and suggest that marijuana-induced memory defects in rodents may be attributable to THC neurotoxicity. Also consistent with this hypothesis is the expression of high levels of cannabinoid receptors in the hippocampus "


"results were detected in ratswith hippocampal lesions, suggesting the possibility ofneurotoxic effects of marijuana in the hippocampus(Morris et al. 1982). In addition, neuronal death andreduced synaptic density and dendritic length ofpyramidal neurons were measured in the hippocampusof chronic marijuana administered rats(Landfield et al.1988; Lawston et al. 2000). Furthermore, THC inducedneuronal death in the neuronal cell lines, culturedhippocampal neurons or hippocampal slices(Chan et al.1998)."

is this information correct?

 
The first study you have listed is a meta data analysis, no actual study took place but a sample of data was selected and used from medical collection. I dont agree with the data collection method but if done correctly it could yield acurate information. To follow their method would require a course in understanding meta data collection so I am forced to disregard it as impossible to prove as unbiased. Could be true, could make their data collection methods easier to follow.

The second study, while interesting, is about 20 years old. It is using extended periods of time and huge doses of thc to show negative results. If however you look at the low dose results they tend to exceed the control even over extended time periods. Mixed reports come from these highly non conclusive type of studies. The fact we are dealing with cultured cells from a rat brain just doesn't seem like this study has any definitive result IMHO.

Due to the vast amount of money currently being thrown at cannabis I would not hold much faith in any studies anymore. Once the mighty pharma corps desire profit, any study to help them achieve that is first to get funded.
 
It is clear now to me. Heavy cannabis consumption for extended periods of time have negative impacts psychologically on people . There is no debate . If you go on pubmed there is much more studies (reliable ones) saying it does. I am talking about not just a few but thousands.
 
markosheehan said:
i have seen a lot of studies lately saying cannabis has morphological changes on brain structure . what could be the implications of these brain changes does anyone know?

http://onlinelibrary.wiley.com/doi/10.1111/pcn.12085/abstract


http://www.jneurosci.org/content/18/14/5322.full
this study says its neurotoxic

"The data reported in our study are consistent with this hypothesis and suggest that marijuana-induced memory defects in rodents may be attributable to THC neurotoxicity. Also consistent with this hypothesis is the expression of high levels of cannabinoid receptors in the hippocampus "


"results were detected in ratswith hippocampal lesions, suggesting the possibility ofneurotoxic effects of marijuana in the hippocampus(Morris et al. 1982). In addition, neuronal death andreduced synaptic density and dendritic length ofpyramidal neurons were measured in the hippocampusof chronic marijuana administered rats(Landfield et al.1988; Lawston et al. 2000). Furthermore, THC inducedneuronal death in the neuronal cell lines, culturedhippocampal neurons or hippocampal slices(Chan et al.1998)."

is this information correct?
Click to expand...

i've been smoking weed almost everyday for almost 6 years now.

this is probably absolutely counterproductive towards HR but my short term memory is absolute shit.

i have lots of cognitive issues and motivational problems.

i've seen these things be associated with heavy cannabis use in the past but i've ignored all signs i've seen because 'it's just weed' right?

idk man i see a lot of people who have smoked heavily throughout their life and you know how you 'become the drug'? i've seen it.

i'm able to hold my own but i'm still young. i have definitely noticed 'frying effects' and this is the drug i indulge in the most.
 
markosheehan said:
It is clear now to me. Heavy cannabis consumption for extended periods of time have negative impacts psychologically on people . There is no debate . If you go on pubmed there is much more studies (reliable ones) saying it does. I am talking about not just a few but thousands.
Click to expand...

I've found a lot of these various medical snippets as well. However, I'm 8 years daily use and for a period of over a year my dose was 525mg thc per day. While I can find many stories placed in my path saying I will hurt myself I cannot find either people who have or results that agree with these medical predictions.

Today I'm using 70mg per day and I barely notice it at all as a high, often for a period of a few minutes I can stop and meditate before I will notice it. If there is a terror at the end of this use I'll be certain to post here, so far there is nothing but positive effects and short term memory has changed. It used to be lost now it is simply stored differently. I don't try to remember in the same way as I used to and the information is there, if I struggle to remember I'll never find it.

I realize I'm a single old man who is a long term canabis addict with an opinion but most of us don't care enough to even write that we don't agree with medical studies because we feel unqualified to comment.

Beyond a change in how I remember and a very real awakening that I think canabis triggered, I haven't experienced negative results. I was a suicidal drunk with nearly 20 years of blind rage from having ptsd and adhd. Now I'm not.

Just because a study has the term medical or a doctor was involved often means little. Most studies (I believe all), have a predetermined result in mind before they are undertaken. Reality is an experience with no predetermined result, you can read about other people's results or find your own. I simply try to remember fearless isn't foolish but fearful is.
 
Well the a lot of the studies I look at are meta analysis studies. I take my studies from pubmed. I check it everyday for new studies that have come out on drugs including cannabis. Some studies say it's only short term cognitive deficits others says it's beyond long term.
From looking at both sides heavy use does seem to have long term affects espically in youths.
I'm thinking about taking charolets web oil which does not have THC. It's seems to weak though to be worth the effort of getting it. Most people say they notice very little.
 
I've read through alot of these studies, and I'll give my 2c on what seems to be well understood what doesn't seem to be well understood scientifically.

Heavy cannabis use over extended periods of time probably has a negative effect on certain types of learning and memory.

Cannabis use during adolescence may have a negative effect on memory retention and IQ.

Cannabis DOES NOT appear to have significant neurotoxicity​, but I wouldn't rule it out at really high doses. Some if the earlier studies that supposedly showed it was neurotoxic had serious design flaws and there's reason to believe that the investigators we're biased. Whether they intentionally biased their experimental design is a matter of debate

Moderate use does not appear to have any significant effects on IQ. I think it does have some minor effects on memory retention.

In sum, I don't think cannabis is harmless, but I do think it's much much safer than most other drugs. I think alcohol is more neurotoxic that THC, and if you use reasonable amounts in moderation, I don't think you have anything to worry about. At the very least, it won't cause permanent damage.

I'll post some good articles later if I have time. There was a recent epidemiological study that was very well controlled, and they didn't find much difference in IQ in even heavy cannabis users.
 
Well you know what they say about ciggarates its not the tobbaco that causes cancer its the 100+ other chemials that each can;)
 
PotatoMan said:
i've been smoking weed almost everyday for almost 6 years now.

this is probably absolutely counterproductive towards HR but my short term memory is absolute shit.

i have lots of cognitive issues and motivational problems.

i've seen these things be associated with heavy cannabis use in the past but i've ignored all signs i've seen because 'it's just weed' right?

idk man i see a lot of people who have smoked heavily throughout their life and you know how you 'become the drug'? i've seen it.

i'm able to hold my own but i'm still young. i have definitely noticed 'frying effects' and this is the drug i indulge in the most.
Click to expand...

You should give those cognitive apps a try. Ive found that they do help with my short term real call in RL. By no means pay for any of them. Just simple shit. If you love cannabis help youre brain utilize it the way you want to.
 
KneelB4Doom said:
You should give those cognitive apps a try. Ive found that they do help with my short term real call in RL. By no means pay for any of them. Just simple shit. If you love cannabis help youre brain utilize it the way you want to.
Click to expand...

IME just making an effort to exercise the mind can work wonders. I feel brain dead if I spend a week doing nothing but smoking, playing video games, watching TV, etc. I feel much sharper when I'm proactive about working on problems, reading, writing, etc.
 
When I smoke I do feel a bit brain dead after I wake up so I almost never smoke and just use edibles. I never feel a 'weedover' from edibles just if I smoke.
 
I feel that video games are somewhat productive theirs so many after all its more productive than the anti social - social media anyway. I love gaming but I try to get myself out every morning in a routine go for a nice walk in my spare time if im not busy etc enjoy the nature maybe have a ciggaratee rarely a spliff but if i smoke on empty stomach i feel sick i didnt used to i used to be able to wake n bake with some of the freshesh nicest 10/10 northen lights literally covered in crystals now the area i live has GOOD stuff but probs not HALF as good as i got and I still cant handle it.


anyway getting back on point getting purpose into your life or just going out going to the park etc when you wake up not go on the computer or tv you can do all that when you get back or anytime they are not going anywhere.
 
even after lots of heavy smoking, everything wit your brain gets back to normal after a week or two
at least in my case, people i know feel the same way

NOT neurotoxic
 
Traumadol said:
even after lots of heavy smoking, everything wit your brain gets back to normal after a week or two
at least in my case, people i know feel the same way

NOT neurotoxic
Click to expand...

I agree. After a week or two, any of the fogginess is gone
 
Its not neurotoxic unless in very high doses (not achieveable unless injected). However brain structure is altered and cognition can be impaired beyond short intoxification. there is evidence out there to suggest memory,psychomotor function,learning,attention,processing ,problem solving and verbal fluency are affected beyond 28 days of abstinence and could some impairment could be permenent in heavy users that started young
 
When you say
markosheehan said:
there is evidence out there to suggest memory,psychomotor function,learning,attention,processing ,problem solving and verbal fluency are affected beyond 28 days of abstinence and could some impairment could be permenent in heavy users that started young
Click to expand...

You should put a link to "out there" so we can all see who is saying these things and what they are basing their opinions on.

In my personal experience marijuana creates an environment that creates dopamine more easily, having a higher level of dopamine allows for expanded cognitive abilities. Problem solving skills for long term heavy users are increased. But I'm a study of 1 done by me so I won't post a link.

If you do have some links to real results from real studies I'd be happy to check them out, I'm very doubtful that marijuana is as harmful as the smoke from the paper but to be fair more people vape or eat the marijuana so the smoke issue isn't as much a danger.
 
https://www.ncbi.nlm.nih.gov/pubmed/28614161

https://www.ncbi.nlm.nih.gov/pubmed/28560818

https://www.ncbi.nlm.nih.gov/pubmed/28414051

https://www.ncbi.nlm.nih.gov/pubmed/28262852

https://www.ncbi.nlm.nih.gov/pubmed/28219487

https://www.ncbi.nlm.nih.gov/pubmed/18358595

https://www.ncbi.nlm.nih.gov/pubmed/19630711

https://www.ncbi.nlm.nih.gov/pubmed/28498718

https://www.ncbi.nlm.nih.gov/pubmed/28364340

The daily use of cannabis over years and decades appears to produce persistent impairments in memory and cognition, especially when cannabis use begins in adolescence (Meier et al., 2012; Volkow et al., 2014a). The neurobiology of the cannabinoid system suggests that these effects may arise because chronic THC use reduces the number of CB1 receptors (i.e. “down-regulates” these receptors) in brain regions that are involved in memory and cognition (Iversen, 2012) Experimental studies suggest that animals exposed to THC during puberty may be more susceptible to these effects of cannabis (Schneider, 2012).
Brain imaging studies comparing school students who are regular long-term cannabis users and non-using students typically find poorer cognitive performance and large decreases in perfusion in the former using SPECT scans (Mena et al., 2013). These changes could partially explain the lower educational attainment and lower grades among chronic cannabis users (Volkow et al., 2014a) and are discussed in more detail in section 6.1.2
Magnetic resonance imaging (MRI) studies have found structural differences between the brains of chronic adult cannabis users and the brains of non-using controls. Changes can be seen in the grey/white matter, in global brain measures (Batalla et al., 2013), and in connectivity (Lopez-Larson, Rogowska & Yurgelun-Todd, 2015). Structural brain abnormalities are seen in CB1-rich areas involved in cognitive functions. In addition, reduced hippocampal volume has been found in neuroimaging studies (Ashtari et al., 2011; Cousijn et al., 2012; Matochik et al., 2005; Yücel et al., 2008). In some studies these reductions persist after abstinence (Ashtari et al., 2011) and have been associated with impaired memory (Lorenzetti et al., 2015). Neuroimaging studies have also found reduced volumes in the amygdala, the cerebellum and frontal cortex in chronic cannabis users (Batalla et al., 2013; Yücel et al., 2008). In a large study population (1574 participants), in which cortical thickness was measured by MRI, an association was found between cannabis use in early adolescence and reduced cortical thickness in male participants with a high polygenic risk score. Adults who have smoked cannabis since adolescence show reduced neuronal connectivity in the prefrontal areas responsible for executive functioning and inhibitory control and in the subcortical networks that are responsible for habits and routines (Volkow et al., 2014a). The precuneous -a node involved in integration of various brain functions such as awareness and alertness – is particularly affected in frequent cannabis users. Long-term cannabis use is hazardous to the white matter of the developing brain, with evidence of axon connectivity damage in three fibre tracts: the hippocampus (right fimbria), the splenium of the corpus callosum, and commissural fibres (which connect the two halves of the cerebral hemispheres). Damage was higher with younger age of onset of regular cannabis use (Volkow et al., 2014a).
The fimbria is a part of the hippocampus involved in learning and memory (Zalesky et al., 2012). These findings are consistent with the observation that impaired memory is a common complaint among cannabis users seeking treatment (Hall, 2015). Recovery of hippocampal connectivity after long-term abstinence has been reported (Yücel et al., 2016). Atypical orbitofrontal functional connectivity patterns were observed in attentional/executive, motor and reward networks in adolescents with heavy cannabis use. These anomalies may be reflected in suboptimal decision-making capacity and increased impulsivity (Lopez-Larson, Rogowska & Yurgelun-Todd, 2015). Chronic cannabis use has also been shown to reduce the brain’s capacity to synthesize or release dopamine (Bloomfield et al., 2014), which could explain why cannabis users have higher scores on negative emotionality (Volkow et al., 2014b).

https://www.ncbi.nlm.nih.gov/pubmed/21321675

THis study ^ is a good one

not all the studies i linked are relevant
 
file:///C:/Users/User/Downloads/Broyd_Cognitive16.pdf

If you can access this it is the best summary
 
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