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Long-term use of psychedelic drugs is associated with differences in brain structure and personality in humans.

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Long-term use of psychedelic drugs is associated with differences in brain structure and personality in humans.

Abstract

Psychedelic agents have a long history of use by humans for their capacity to induce profound modifications in perception, emotion and cognitive processes. Despite increasing knowledge of the neural mechanisms involved in the acute effects of these drugs, the impact of sustained psychedelic use on the human brain remains largely unknown. Molecular pharmacology studies have shown that psychedelic 5-hydroxytryptamine (5HT)2A agonists stimulate neurotrophic and transcription factors associated with synaptic plasticity. These data suggest that psychedelics could potentially induce structural changes in brain tissue. Here we looked for differences in cortical thickness (CT) in regular users of psychedelics. We obtained magnetic resonance imaging (MRI) images of the brains of 22 regular users of ayahuasca (a preparation whose active principle is the psychedelic 5HT2A agonist N,N-dimethyltryptamine (DMT)) and 22 controls matched for age, sex, years of education, verbal IQ and fluid IQ. Ayahuasca users showed significant CT differences in midline structures of the brain, with thinning in the posterior cingulate cortex (PCC), a key node of the default mode network. CT values in the PCC were inversely correlated with the intensity and duration of prior use of ayahuasca and with scores on self-transcendence, a personality trait measuring religiousness, transpersonal feelings and spirituality. Although direct causation cannot be established, these data suggest that regular use of psychedelic drugs could potentially lead to structural changes in brain areas supporting attentional processes, self-referential thought, and internal mentation. These changes could underlie the previously reported personality changes in long-term users and highlight the involvement of the PCC in the effects of psychedelics.

Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

 

 

http://www.ncbi.nlm.nih.gov/pubmed/25637267

 

 

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Interesting stuff. The full-text is apparently available here, or via sci-hub.bz (sci-hub.io is down/blocked). The full discussion is well worth reading.

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Thanks for the Link Yeti

That was an interesting read, although a lot of it didn’t make sense to me.

 

RESULTS

Figure  1  shows  the  CT  statistical  maps  for  the  comparison  between  ayahuasca  users and  their  matched  controls. 

Table  2  shows all  clusters  in  which  CT  was  found  to  be significantly different between groups. Thinning was observed in the ayahuasca-using group in  six  cortical  areas:  the  middle  frontal  gyrus,  the  inferior  frontal  gyrus,  the precuneus,  the superior frontal gyrus, the posterior cingulate cortex (PCC), and the superior occipital gyrus.

Can anyone explain why this thinning would be observed, and whether or not it’s a good or bad thing?

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Yeah, I'm not sure either - I didn't think they made a clear judgment either way on the thinning was good or bad - possibly because it's not as simple as that. I thought there was some thickening mentioned elsewhere, and I'm fairly sure they detected no deficits in the ayahuasca users. I'll have to re-read (carefully). Wasn't there another paper in the past few years on the psychological capabilities etc. of long-time ayahuasca users? I think @Alchemica would give a good perspective on this too.

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18 hours ago, Yeti101 said:

Interesting stuff. The full-text is apparently available here, or via sci-hub.bz (sci-hub.io is down/blocked). The full discussion is well worth reading.

Sci-hub IP is still working fine :)

Here

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Yer i couldn't find a clear judgement on whether or not cortical thinning was good or bad. It seemed like the ayahuasca users had similar results in the personality tests. 

 

Ive had a little search around the webs this morning and found cortical thinning is associated with  ADD, Psychopathy, and Schizophrenia 

 

http://www.ncbi.nlm.nih.gov/pubmed/19730275

http://www.ncbi.nlm.nih.gov/pubmed/22581200

http://www.ncbi.nlm.nih.gov/pubmed/26802780

 

What i find interesting about this study is that all participants were members of the Santo Daime Church, and were found to have significant differences in brain structures which included cortical thinning. However they were not found to have significant psychological difference, which indicates to me the possible protective effects that being a member of a church can have on psychological outcomes. 

 

Id like to see a similar studied performed on regular ayahuasca drinkers who are not members of the Santo Daime Church, it would be interesting to make a comparison. 

 

 

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Who actually frequently consumes that stuff? As a drink.
Smoking i can understand, but the drink? MAOi's are dangerous, its the chemical equivalent of doing drugs intravenously compared to eating them, relative to the risks.
Though, many people on them i suppose do just fine with a list of things to avoid, like grapefruit, i think.

It is interesting though, how religion affects psychopathy. Religion kind of pre-sets a way of living, to a textbook, a psychopath would fit right in since fitting in literally just means following the book, rather than freestyle imitating and analyzing cues and all that, how they interpret social activity manually or increasingly so with severity of psychopathy.

 

I rather though dont like the title here, because your kind of representing any and all psychedelics at face value, so, any preceding commentary immediately implies the negative effects of DMT+MAO inhibitor, an inherintly risky drug which i am confident in my understanding its not that common or regularly used, opposed to, safer ones, wether harder or lighter in effect.
Immediately i thought maybe this would be about psilocybe mushrooms



 

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8 hours ago, Change said:

Ive had a little search around the webs this morning and found cortical thinning is associated with  ADD, Psychopathy, and Schizophrenia.

 

 

But clearly not all cortical thinning is associated with these conditions. As the article says, another study http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0042421 has found that ayahuasca users exhibit less mental illness than other groups, and even appear to show some cognitive enhancement! Is the fact that these people were members of a particular church the reason for this - especially the cognitive enhancement? 

 

I don't know the answer to that, but I'll offer a few observations.

 

1. 2 of the 3 articles you link to have some pretty severe limitations in that they have just tested for cortical thinning in kids diagnosed with ADD, inmates categorised as psychopaths (don't get me started on psychopathy!). Only Watsky et al tested for CT in healthy people.  Even Watsky's hypothesis is kind of boned if Bouso (2015) is right; the correlation between cortical thinning and schizophrenia might not always be that strong.

 

2. 'Cortical Thinning' is not super specific. The original article talks about thinning in very specific areas of the cortex. The other papers talk about 'widespread thinning', or thinning across 'a number of regions'. I'd have to read the full articles to be sure, but this might be a of an apples and oranges comparison. 

 

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I thought it was interesting the control group drunk alcohol allot more frequently. seems not so controlled imo. 

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Thanks for your response Yeti, 

 

 

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@Yeti101 From my (limited) perspective and without reading the article, thinning of a key node of the DMN could be beneficial: "breaking the dominance of the default mode network may also be what underpins the success of psychotherapies for treating depression. These include cognitive behavioural therapy (CBT) and mindfulness-based cognitive therapy (MBCT), which aim to help patients “decenter” their thinking, identifying less with their thoughts and emotions" [1].  Other thinning I'm not sure about. I'll read the article later on and see if I have anything to contribute.

 

Other research has indicated ayahuasca intake is associated with increases in mindfulness capacities...

For a less technical overview see:
http://reset.me/study/study-long-term-use-of-ayahuasca-linked-to-changes-in-personality-and-brain-structure/

Edited by Alchemica
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On 29 May 2016 at 6:42 PM, drpotato said:

Who actually frequently consumes that stuff? As a drink.
Smoking i can understand, but the drink? MAOi's are dangerous, its the chemical equivalent of doing drugs intravenously compared to eating them, relative to the risks.
Though, many people on them i suppose do just fine with a list of things to avoid, like grapefruit, i think.

It is interesting though, how religion affects psychopathy. Religion kind of pre-sets a way of living, to a textbook, a psychopath would fit right in since fitting in literally just means following the book, rather than freestyle imitating and analyzing cues and all that, how they interpret social activity manually or increasingly so with severity of psychopathy.

 

I rather though dont like the title here, because your kind of representing any and all psychedelics at face value, so, any preceding commentary immediately implies the negative effects of DMT+MAO inhibitor, an inherintly risky drug which i am confident in my understanding its not that common or regularly used, opposed to, safer ones, wether harder or lighter in effect.
Immediately i thought maybe this would be about psilocybe mushrooms

 

There are a number of people who consume this beverage regularly, especially overseas. Pharmaceutical MAOIs can be dangerous but the alkaloids in caapi and rue are RIMAs and dietary considerations aren't anywhere near as serious as with pharms. Some diet restrictions are important if you want to avoid painful purging especially if you consume the beverage often but to compare  maois to shooting something up in terms of safety is just very ignorant unless you're blindly mixing them with other drugs but that too is ignorant. The particular combo in question is not inherently dangerous though and no more dangerous than other psychedelics.

 

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My 2 cents.

 

In the same vein as Alchemica above, I would assume a reduction in DMN dominance due to cortical thinning would be of benefit. Certainly the TPN (Task Positive Network) are the 'parts' of the brain associated with mindfulness, meditation and good stuff like that. It is also the case that tryptamines reduce blood flow to the DMN, ostensibly increasing connectivity (and possibly corresponding blood flow?) to the TPN.

 

Perhaps cortical thinning is an indicator that the DMN is not as dominant in terms of 'usage' by said users?

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