A short thread on DMT exceptionalism inspired by
this recent paper
nature.com/articles/s4139…
There's a lot of folklore about DMT. It's potent, evokes "entity encounters," & produces no tolerance. I'm not convinced that DMT is a special case of psychedelic in any of these areas. 1/7 mg for mg, DMT is less potent than psilocybin. 1-2 mg intravenous psilocybin (doi.org/10.1016/S0031-…, doi.org/10.1073/pnas.1…) produces similar effects as 10+ mg intravenous DMT (doi.org/10.1001/archps…, doi.org/10.1007/s13318…, doi.org/10.1038/s41398…). 2/7

A review on psychoactive drugs & emotional episodic memory I started at the end of my PhD (better later than never...) Drugs & memory are typically studied in terms of conditioning/habit learning, but initial conscious experiences under drugs...

1/21sciencedirect.com/science/articl… ...may also play a role in future drug (ab)use. Episodic memory may be a bridge between early drug use & addiction. Alterations in emotional episodic memory may also be involved in the therapeutic efficacy of certain drugs currently under investigation (e.g., psychedelics).
2/21

Immediate-onset but not delayed-onset PTSD associated with hallucinogen use:
onlinelibrary.wiley.com/doi/10.1002/jt…
Assuming this effect is reliable, if it were simply self-medication, one has to wonder why those that develop PTSD later are not also using hallucinogens. 1/4 One possibility is that using hallucinogens while a traumatic event is still fresh and one is still sensitive to this trauma could increase the likelihood of developing PTSD. Many psychedelic users do tend to avoid using psychedelics soon after something traumatic happened. 2/4

Not sure who needs to hear this :coughReviewer2cough: but a drug effect is not strictly on consolidation unless the drug is administered AFTER encoding. A 🧵 for how to enhance your memory w/alcohol, how to get false memories w/THC, & how psychopharmacology gets this wrong. 1/10 Giving a drug before encoding impacts encoding. If the effect only shows up after a delay between encoding and retrieval (≥24 hours), the drug's effect is still on encoding, but it's dependent on a period of consolidation (w/o the drug necessarily impacting consolidation). 2/11

In my talk on Monday, I discussed how psychedelics probably evoke 𝑝𝑟𝑒𝑠𝑞𝑢𝑒 𝑣𝑢/illusory insights, and these feelings of insight can be misattributed to ideas and mental imagery conjured up during a trip. I'm sure some people disagree with me, but consider this... 1/5 Last week, a paper came out showing that semantic priming can evoke illusory insights (under sober conditions). 2/5
link.springer.com/article/10.375…

Although some have speculated that #psychedelics produce enduring enhancements of cognitive flexibility, here we finally show that psilocybin therapy enhances cognitive and neural flexibility in major depressive disorder. However, there's a caveat. 1/10
nature.com/articles/s4139… As previously reported, depression was reduced (doi.org/10.1001/jamaps…; see variability in single subject data provided here), but also cognitive flexibility (measured as a 𝑑𝑒𝑐𝑟𝑒𝑎𝑠𝑒 in perseverative errors) was enhanced 1 week post-psilocybin therapy. 2/10

First real microdosing study reveals that low doses of #LSD increase estimation of time intervals:
link.springer.com/article/10.100…
The authors refer to to this as "temporal dilation." However, similar to drug studies in episodic memory, there's an encoding vs. retrieval problem here. 1/n If participants encode the initial interval in a temporally dilated state (time is perceived to be longer), then their reproductions will be longer. However, if the passage of time feels longer during reproduction, then shorter intervals should be reproduced. 2/n