New research sheds light on the different types of subjective experiences produced by five different types of psychedelic substances. The study, published in Psychopharmacology, used computer algorithms to analyze thousands of anonymously published reports about the effects of psychedelic drugs.
A growing body of research indicates that psychedelic drugs like 3,4-methylenedioxymethamphetamine (MDMA) and psilocybin hold potential for the treatment of psychiatric conditions such as depression and post-traumatic stress disorder. While it is known that psychedelics induce profound changes in perception and consciousness, little research has quantified the different experiences associated with consuming these substances, especially in a naturalistic context.
“Though it has not been my main research focus previously, I was often fascinated by promising findings from studies examining psychedelic treatments for various mental disorders in patients who were unresponsive to standard treatments,” said study author Adrian Hase, a postdoctoral researcher at the University of Fribourg.
“The psychiatric research group I am now part of focuses on stress and psychopathology, but also conducts basic research into the effects of psychedelic substances. We often talk about the topic and one day came up with this idea of analyzing online experience reports to compare various psychedelic substances.”
The researchers used software called Linguistic Inquiry and Word Count (LIWC) to analyze the content of 2,947 online reports from the Erowid experience vault. The sample included 971 reports about psilocybin-containing mushrooms, 671 reports about LSD, 312 reports about DMT, 163 reports about ketamine, 68 reports about ayahuasca, and 236 reports about antidepressant medication.
“There were important differences in how people wrote about their experiences with psychedelics, depending on which substance was used,” Hase told PsyPost. “The language in the psychedelic substance report groups that we analyzed clearly differed from that of a group of control reports (describing use of antidepressant drugs), but there also were differences between the different psychedelic substances. Differences were found on language outcomes related to affective processes (positive, negative, sadness, and anxiety words), cognitive processes, analytical thinking, psychedelic experience, and mystical experience.”
For example, compared to the other substances, reports about ayahuasca and DMT tended to contain relatively few words related to emotion but had more language associated with analytical thinking. In contrast, reports about MDMA tended to include more emotional language and a high proportion of cognitive process words but relatively little language associated with analytical thinking.
The researchers also found that ayahuasca and DMT reports featured the greatest semantic similarities with the Altered States of Consciousness Rating Scale and Hood’s Mysticism Scale, followed by psilocybin and LSD. Unsurprisingly, antidepressant medication reports had the least semantic similarities with the psychedelic and mystical experience scales.
“The research is highly interesting, but due to our methodology there are some caveats,” Hase said. “The most important thing to note is that we sourced online experience reports and did not actually administer the analyzed substances. Thus, it would be very interesting to replicate our present findings in an experiment where participants receive the substances and detail their experience in a controlled setting. This would answer the question of whether the psychedelic substances themselves or other variables (e.g., expectations, trip setting, demographic factors) are responsible.”
“We would like to note that we do not promote illicit drug use and hope that this article can contribute to education and harm reduction,” the researcher added. “We also applaud the tireless work of the Erowid Center, a non-profit educational organization that provides the online repository from which we sourced the analyzed reports.”
The study, “Analysis of recreational psychedelic substance use experiences classified by substance“, was authored by Adrian Hase, Max Erdmann, Verena Limbach, and Gregor Hasler.
