New study finds psilocybin leads to increased altruism 6 months later

Cross-posted to the Enthea site.

Griffiths et al. 2017 was published recently; it had some impressive findings.

The study looked at psilocybin administration alongside a regimen of nonsecular spiritual practices (meditation, introspective journaling). The study compared a group who received a very low (placebo-level) dose of psilocybin & "standard" support from spiritual practice guides (LD-SS) to a group who received a high dose of psilocybin & standard support (HD-SS), to a group who received a high dose of psilocybin & a high level of support (HD-HS). Follow-up was 6 months after the psilocybin sessions:

The study collected data from numerous measures, and many robust between-group differences were found. Here are the effect sizes (Cohen’s d) of some of these differences:

  • Altruism: Comparing LD-SS [low dose, standard support] to HD-SS [high dose, standard support], the effect size was 1.36, which statisticians consider “very large.” Comparing LD-SS to HD-HS [high dose, high support], the effect size was 1.95, considered “very large,” almost “huge.”
  • Trait Forgiveness Scale: Comparing LD-SS to HD-HS, the effect size was 0.55, and comparing LD-SS to HD-HS, the effect size was 0.64. Both are considered “medium” effect sizes.
  • Interpersonal Closeness: Comparing LD-SS to HD-SS, the effect size was 0.82 (considered “large”). No significant difference was found between HD-SS and HD-HS.
  • “How personally meaningful was the experience?” This measure yielded the largest effect size seen in the study, 2.47 (considered “huge”), shown between the LD-SS and HD-HS conditions.

Participants were asked to rate the spiritual significance of their experience in the study. Consistent with the positive changes in various traits, 12% of the LD-SS group, 76% of the HD-SS group, and 96% of the HD-HS group rated their experience as among the top 5 most spiritually significant of their lives. Zero percent, 40%, and 56%, respectively, rated it as the single most spiritually significant.

Above summary pulled from this article (a).

Reasons this study is exciting:

  • Large effect sizes on a bigger sample. Griffiths et al. 2008, an earlier study following a similar protocol, had 36 participants complete the study. Griffiths et al. 2017 had 75 participants complete, and found large increases in altruism, positive behavior change, and spirituality in the psilocybin groups (see Figure 5, p. 14).
  • Unlikely to be a placebo effect. Griffiths et al. 2008 compared a high psilocybin dose to a active placebo of methylphenidate (Ritalin). Ritalin has a pretty different psychoactive profile than psilocybin, so study participants may have been able to determine which drug they were given, exposing them to expectancy effects. In contrast, the new study compared a very low dose of psilocybin (1 mg / 70 kg) to higher doses of psilocybin (20 and 30 mg / 70 kg). A very low dose of psilocybin has a similar (though much subtler) psychoactive profile to a high dose, so blinding was less likely to be broken than in previous studies.
  • Not p-hacked. Griffiths et al. 2017 measured many variables; many of these showed significant differences between the low-dose and high-dose groups at p < 0.001 (see Table 5 on p. 13 and Table 6 on p. 15). All results were planned comparisons. Because of the number of  p < 0.001 significant results, it's highly unlikely that the results were p-hacked.


And a couple notes of caution:

  • No increase in Openness. MacLean et al. 2011, a follow-up to Griffiths et al. 2008, made waves by finding increases in psychological Openness 14 months after the psilocybin session. The new study followed a similar protocol, but didn't find an increase in Openness at 6-month follow-up. The study authors didn't give a compelling reason for not finding an increase – from p. 15, "The failure to observe significant increases in Openness in the current study may be attributable to engagement in the program of spiritual practices or to some other aspect of the study design."
  • No change in day-to-day spiritual practice. Griffiths et al. 2017 tested psilocybin administration alongside a regimen of nonsecular spiritual practices. Though the high-dose psilocybin groups experienced greater subjective spirituality, "The study did not provide evidence that psilocybin dose affected engagement with spiritual practices." (p. 13). So psilocybin administered in this format may not cause behavior change; the value of subjective assessments of experience relative to the value of concrete behavior changes is likely a disputed topic.

Comments (5)

Comment author: Ben_West  (EA Profile) 18 October 2017 01:59:12PM 1 point [-]

Do you know how they measured altruism? It seems like maybe they are using "altruism" as a synonym for the "relationships" questionnaire?

Comment author: Milan_Griffes 18 October 2017 10:18:54PM 1 point [-]

Update: I checked with the study author and he confirmed that "relationships" on p. 5 is the same as "social effects" in Table 5.

Comment author: Ben_West  (EA Profile) 19 October 2017 10:39:02PM 3 points [-]

Thanks Milan! Do you know more about how they defined "relationships" ("altruism")? Given that they think "relationships" and "altruism" are synonymous, it seems possible that the definition they use may not correspond to what people on this forum would call "altruism".

Comment author: Milan_Griffes 23 October 2017 04:04:53PM 1 point [-]

I don't. I asked the author to share the survey instrument; he hasn't gotten back to me yet.

Comment author: Milan_Griffes 18 October 2017 02:33:38PM *  0 points [-]

I think the "altruism" measure is an aggregate of some of the "persisting effects questionnaire" questions. (p. 5)

Not sure if it maps directly to the relationships portion of that questionnaire, but I bet it does (all of the other categories on p. 5 cleanly map to results in Table 5, so by elimination "relationships" = "altruistic / positive social effects" )