The insula and an alternative interpretation of the psychotherapeutic use of psychodelics
There is now a growing body of evidence about the potential psychotherapeutic usability of psychodelic substances, such as ketamine, LSD, ibogaine and psylocibin, in treatment of issues like depression,PTSD or substance addiction. While nothing decisive can be said yet, the treatment potential does seem promising, with further studies coming in as more are allowed. (Since most psychodelics fall under various controlled substances acts, obviously the ease in studying them is lesser than in the case of, let’s say, buprioprion.)
The typical interpretation of how such an experience could be effective tend do concentrate on the psychodelic experience itself, it’s intensity, the “mystical experience”, etc. However, an interesting alternative seems to be at hand.
Now the insula is a bit of a neurological dumpster, basically any function that doesn’t seem to fit appears to be connected with this area. It has been connected with empathy, taste, homeostasis, introception, bits of conciousness, emotion interpretation, etc. More interestingly, it while it has no direct connection to the dopamine-based mesocortical motivational network, it has been suggested that the insula contains the introceptive representations of addiction states (or perhaps pleasure states in general). Damage to the insula has been shown to cause an extreme ease in quitting addictive behaviors, in a way “resetting” how the brain reacted to the possibility of using them. It wasn’t as if there was a decrease in dopamine levels in themselves, it’s simply that increased addiction stimuli did not lead to addiction cravings, as if the content of the addiction had been removed.
We know that psychodelic drugs influence the insula, among other areas, and that changes in the insula are connected to halucinatory experiences, including “unity” and “communion with god” states , as are the 5-HT 2A receptors stimulated by most psychodelics. So the interesting possibility here is this – are we perhaps mistaking the side effect for the cause?
Is it possible that the psychodelic effects of the various drugs are so salient, that we automatically assume them to be the cause of the changes coming out of such experiences, while in fact they are simply something in addition to the main change happening – the “reset” of the insular database for introspective representations? With the connection of a “strong enough” mystical experience being basically “having enough of the drug that it not only impacts the general insular area, but actually reaches that very area participating in the storage of introspective representations. This would, in fact, be quite in tune with other observed potential benefits in case of PTSD and depression. After all, if too positive introspective images might lead to addiction, representations not attractive enough might be a good explanation for depressive ahedonia and a similar damage to representations connected with PTSD – we do know a dopamine deficiency is involved there as well.
The practical and clinical significance of this distinction is actually rather large. While I am fully for the legalisation of psychodelic drugs (with proper education), I realize that for most of the world it will take several decades before such a change will be implemented. As such, research on the psychotherapeutic use of psychodelics will be quite stimied, and their popular introduction even so, remaining basically an option for the rich (as with the currently available ketamine treatments) or for these willing to risk breaking the law or engage in drug tourism – which, obviously, poses extra challenges to people struggling with depression. However, if it turned out that the psychoactive aspect of the experience is a side effect and we just needed to focus on properly stimulating a specific section of the insula – now that is something which might be implemented in practice with far, far less political resistance, with a huge benefit for these needing help from such treatment.
An interesting way of verifying this (although, because this is a deep-brain structure, somewhat difficult) would be through the use of transcranial magnetic stimulation on the insula as a way of treating addiction. In fact I was pleased to see I wasn’t the first to come up with the concept, and some preliminary studies are already being proposed and performed.