It's humorous to me that they bothered injecting saline into the control group here. I'm pretty sure anyone on earth would know whether or not they were on 75 micrograms of LSD, and the act of wondering whether you are or not is enough to induce panic. Pretty sure both groups would produce higher quality data in an unblinded study.

No expert, but I had some immediate questions when reading this. Wasn't the dose high enough to be easily distinguishable from the placebo without any experience? Why not some other drug a palcebo? Is single blind design actually advisable in such a study? Can someone enlighten me?

The double-blind thing seems a little pointless here, 75ug is on the small end of dosage but close to the informal 'standard' dose of 100uh, and intravenous delivery means very rapid onset compared to oral administration. It might have been more interesting to try with low doses that wouldn't necessarily give the feeling of tripping (visual artifacts etc).

The result is interesting but feels a bit like a formal statement of what everyone already knew to be distinctive about psychedelics. The actual numbers don't seem that dramatic. I'm a little skeptical about the drive to rehab LSD as a therapeutic product - both because I have doubts about mediation of psychedelic experience by clinicians, and because of the relatively long metabolic half-life, with a psychoactive dose typically lasting 8-12 hours. The combination of LSD and for-profit healthcare delivery as practiced in the US seems like an extremely poor match.

“Computational modelling revealed that the most pronounced effect of LSD was the enhancement of the reward learning rate. The punishment learning rate was also elevated. Stimulus stickiness was decreased by LSD, reflecting heightened exploration. Reinforcement sensitivity differed by phase.

Conclusions

Increased RL rates suggest LSD induced a state of heightened plasticity.”

Would love to see this type of experiment performed across different dosages, 25 μg -200 μg. I think the "positive" effects would take a big, sudden drop after a certain threshold

This is a rather strange definition of 'learning', a better term would be 'behavioral modification.' Here's a definition of the practice:

> "From an affective neuroscience perspective, our understanding of psychiatric illness may be advanced by neuropsychological test paradigms probing emotional processes. Reversal learning is one such process, whereby subjects must first acquire stimulus/reward and stimulus/punishment associations through trial and error and then reverse them. (2009 Cambridge Pyschological Medicine, Dickstein et al.)"

This is pretty low-level stuff, e.g. 'learning' that red means stop and then 'relearning' that red means go, etc. The authors claim to have developed evidence that LSD is associated with plasticity in healthy humans suffering no psychological disorders.

It's an interesting study, I suppose. Psychedelics are often called 'mind-expanding' and it's possible that the underlying neurochemical mechanism of action facilitates breaking out from fixed behavior patterns. This might also explain some of the reasons why authoritarian governments don't like psychedelics as they might encourage a loss of faith in authorities, or cause religious fundamentalists to reconsider their belief systems etc.

After all, if you can't necessary trust your sensory organs to give you reliable information about the world around you due to the influence of a complex molecule on a receptor protein in your brain, perhaps blind faith in the pronouncements of politicians, priests, and media talking heads is not justified either?

In terms of learning, however, I've always thought that most notable psychedelic effect was the development of good three-dimensional visualization of complex objects, such as electrical fields or proteins and DNA and things like that. Such visual effects are generally associated with higher doses however, which are a bit tricky to manage safely, and so require special attention to optimal set and setting.

I'm more scared of LSD than ever before, after hearing about that you see "scanlines" for ever after using it. Anyone got this after?

https://www.insider.com/9-years-after-acid-trip-man-has-pers...

Complete BS study. Increased exploration reduces reward learning rate. That’s the whole point of explore-exploit trade off which is at least NP hard.

The way they refer to RL dynamics as “RL rates” is also a give away that these people don’t understand RL. I’ll leave the evaluation of their cognitive science merit to people knowledgeable in that area