• N&PD Moderators: Skorpio | thegreenhand

Chronic neurotoxicity of ketamine is readily visible by MRI (Wang et al., 2013)

nuke

Bluelighter
Joined
Nov 7, 2004
Messages
4,191
Paper is free here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3713393/

Ketamine, a known antagonist of N-methyl-D-aspartic (NMDA) glutamate receptors, had been used as an anesthetic particularly for pediatric or for cardiac patients. Unfortunately, ketamine has become an abusive drug in many parts of the world while chronic and prolonged usage led to damages of many organs including the brain. However, no studies on possible damages in the brains induced by chronic ketamine abuse have been documented in the human via neuroimaging. This paper described for the first time via employing magnetic resonance imaging (MRI) the changes in ketamine addicts of 0.5-12 years and illustrated the possible brain regions susceptible to ketamine abuse. Twenty-one ketamine addicts were recruited and the results showed that the lesions in the brains of ketamine addicts were located in many regions which appeared 2-4 years after ketamine addiction. Cortical atrophy was usually evident in the frontal, parietal or occipital cortices of addicts. Such study confirmed that many brain regions in the human were susceptible to chronic ketamine injury and presented a diffuse effect of ketamine on the brain which might differ from other central nervous system (CNS) drugs, such as cocaine, heroin, and methamphetamine.

Wang C, Zheng D, Xu J, Lam W, Yew DT. 2013. Brain damages in ketamine addicts as revealed by magnetic resonance imaging. Front Neuroanat. 2013 Jul 17;7:23. doi: 10.3389/fnana.2013.00023.

Quite a lot of extensive, diffuse damage is visible in the heavy users, but there are even visible changes for the light user (200 mg twice a week). Polydrug use is again a problem, and the authors discuss lesions arising from other drug use in the discussion section.
 
"pain altercations?" It drives me nuts when papers don't get copy edited.

1. Well, this study ruined my day
2. I don't understand why they didn't use more age- and sex-matched controls, given n = 21.
3. This would be much more convincing evidence if it was longitudinal in nature

Luckily, I have some very nice pre-ketamine brain studies around somewhere. Maybe I'll try to get re-imaged in a few months, and cut back from daily dosing in the meantime. On the other hand, I'd rather have my MR findings report a couple "hyperintense spots" on T2WI than a 9 mm bullet hole. Maybe it's time for ECT. FML.

ETA: what is the "schizophrenic like behavior/psychosis" they refer to, other than schizophrenics often present with psychosis?
 
I don't know about neuroscience....but in my field most papers from china are full of false/exaggerated data and generally not even taken seriously. Again, I don't know about neuroscience or this specific group, but the reputation of science done in that part of the world, under pressures from bosses, parents, and even the government is to be taken with a hefty grain of salt until verified by other outside research groups,

and to think this is where we are all getting our drugs from, the same place that often ends up poisoning their manufacured foods, we are trusting them to give us clean illegal drugs. since our own governments won't let us do it, nor profit from it, I guess we have to let them get rich and poison us since jesus told the president drugs are bad.
 
So are we finally able to say Olney's lesions occur in humans now? ;)

I don't know about neuroscience....but in my field most papers from china are full of false/exaggerated data and generally not even taken seriously. Again, I don't know about neuroscience or this specific group, but the reputation of science done in that part of the world, under pressures from bosses, parents, and even the government is to be taken with a hefty grain of salt until verified by other outside research groups

I've only run across a small handful of recent chinese neuroscience that I'm heavily skeptical of, not too different from anywhere else. I wouldn't be quick to discredit the information given the source. These are also researchers from The Chinese University of Hong Kong, not exactly shittywok cormmunity correge.

I definitely don't disagree with your appraisal of typical chinese pharmaceutical exporters though =D
 
I think there's enough room to poke holes in this study's methodology without also needing to go after the nationality of the researchers, but Front Neuroanat has an impact factor of 4+, which is pretty solid as far as (obviously flawed) impact factors go. However, with all the talk of Chinese scientists receiving $50K-$100K cash bonuses for landing an article in Science or Nature, some random numbers I pulled off the web stated that a journal in the 3 to 5 range would be a cash bonus of around $611. I don't know how much these scientists make per year, and I would have loved it someone threw a random $600 at me for publishing, especially in grad school, but it's not the kind of monetary figure that screams scientific misconduct.

I would also love to see some functional imaging of the same addicts, and better yet, some correlations with pathology, but I doubt that would get past the IRB. In the meantime, I give them credit for getting the marginal information they do have out there. Hopefully it will spark some interest in some more of the same. Maybe a start would be some short- to mid-term before-and-after scans of patients in palliative care populations newly receiving ketamine for pain management.
 
I think there's enough room to poke holes in this study's methodology without also needing to go after the nationality of the researchers, but Front Neuroanat has an impact factor of 4+, which is pretty solid as far as (obviously flawed) impact factors go. However, with all the talk of Chinese scientists receiving $50K-$100K cash bonuses for landing an article in Science or Nature, some random numbers I pulled off the web stated that a journal in the 3 to 5 range would be a cash bonus of around $611. I don't know how much these scientists make per year, and I would have loved it someone threw a random $600 at me for publishing, especially in grad school, but it's not the kind of monetary figure that screams scientific misconduct.

I would also love to see some functional imaging of the same addicts, and better yet, some correlations with pathology, but I doubt that would get past the IRB. In the meantime, I give them credit for getting the marginal information they do have out there. Hopefully it will spark some interest in some more of the same. Maybe a start would be some short- to mid-term before-and-after scans of patients in palliative care populations newly receiving ketamine for pain management.


The "Frontiers ..." series of journals are all open-access author pays to publish style. That means the authors likely had to pay hundreds of dollars up front just to get this paper to print, I doubt the $600 figure you're quoting would even cover that.


Anyways, neuroimaging can be so fickle. It's so hard to tell whether these reductions are significant in any way, or whether they generalize beyond the small pool they sampled from. In my experience the only way to judge a study like this is to wait and see if other groups can replicate, unfortunately.
 
Good thing publishers are biased against 'mere' replications. ;)

ebola
 
Larger number of subjects undergoing imaging with a broader range of ages and more controls. I don't think 400 mg of ketamine a week is "light use" I'd say it's more habitual but on a low end of addiction. Some subjects dosing once doing 500 mg a month as a further reference data to build up a more concise picture of the degrees of use/misuse and possible brain damage. Otherwise a worthwhile read and a reasonably well constructed publication.
 
Good thing publishers are biased against 'mere' replications. ;)

ebola

That's not always the case with clinical trial results. If someone takes the time and effort to do the trial some journal will pick it up, even if the results are completely negative or a duplicate of another trial.
 
But is there still a reduced statistical chance of publishing and wide readership? If so, it boosts the possibility of type 1 error of a sort that other studies won't take into consideration when testing their hypotheses. I corroborate that this trend is much worse in other fields, particularly social sciences.

ebola
 
Top