Rats on psychedelics show mixed results


Rodent study adds more evidence to gauge increasing popularity of microdosing. Nick Carne reports.


Tiny but regular doses of DMT appear to produce largely positive outcomes in rats.

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New research suggests there are upsides and downsides to taking psychedelic drugs.

That won’t surprise anyone who does remember the 60s, but in this case the finding is academic rather than anecdotal, and it deals with the more modern concept of microdosing – taking tiny amounts of hallucinogens to boost mood and mental acuity.

The practice is gaining popularity and publicity because of reports, and early research, suggesting it works.

A recent Australian study, for example, found positive outcomes for 98 microdosers tracked, while Canadian research noted that “current and former microdosers” fared better than a control group on measures of dysfunctional attitudes, negative emotionality, wisdom and creativity.

Now, researchers at the University of California, Davis, in the US have published findings on their work with rats, in a paper in the journal Chemical Neuroscience.

"This is the first time anyone has demonstrated in animals that psychedelic microdosing might actually have some beneficial effects, particularly for depression or anxiety,” says research leader David Olson.

But there’s a rider. “It's exciting,” he says, “but the potentially adverse changes in neuronal structure and metabolism that we observe emphasise the need for additional studies."

Olson's group gave male and female rats N,N-dimethyltryptamine – better known as DMT, a psychedelic compound found in ayahuasca tea. DMT's molecular structure is embedded within the structures of popular microdosing drugs such as LSD and psilocybin.

There is no accepted definition of what constitutes a microdose, but those who do it tend to take one-tenth of a "trip" dose every three days, so that’s what the researchers did. Rats received one-tenth of the estimated hallucinogenic dose, based on body weight, every third day for two months.

After two weeks they began being tested for mood, anxiety and cognitive function during the two days off – and the results were enlightening.

DMT microdosing helped rats overcome a "fear response" in a test considered to be a model of anxiety and post-traumatic stress disorder (PTSD) in humans, and the researchers found reduced immobility in an experiment that measures the effectiveness of antidepressant compounds.

In tests of cognitive function and sociability, no obvious impairments or improvements were found, which contrasts with human anecdotal reports.

On the downside, the team noted some potential risks: the dosing regimen significantly increased bodyweight in male rats, for example, and caused neuronal atrophy in females.

The latter change was unexpected, because in previous studies rats treated with a single high dose of DMT showed increased neuronal growth. This suggests an acute hallucinogenic dose and chronic, intermittent low doses of DMT produce very different biochemical and structural phenotypes.

The findings also suggest it's possible to decouple the hallucinogenic effects from the therapeutic properties of these compounds, which could be important.

"Our study demonstrates that psychedelics can produce beneficial behavioural effects without drastically altering perception, which is a critical step towards producing viable medicines inspired by these compounds," Olson says

  1. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0211023
  2. https://link.springer.com/article/10.1007/s00213-018-5106-2
  3. http://dx.doi.org/10.1021/acschemneuro.8b00692
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6088236/
  5. https://www.livescience.com/54813-ayahuasca.html
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