Large Study Of Microdosing Psychedelics Shows Benefits but also the Power of Placebo

I've been rather skeptical of microdosing and have long been eagerly anticipating rigorous scientific research results.  Now we finally have some published data in the form of this study.  Imperial College London, on a shoestring budget, got 191 participants to prepare their own microdoses AND placebos by putting microdoses (of their own choosing and sourcing) into opaque capsules (so you could not tell which ones were empty vs. containing the microdose).  Participants could use whatever psychedelic they were used to, in whatever dosage they were used to.  Psilocybin-containing mushrooms were used by 23% of the sample, 14% used legal LSD analogues (such as 1P-LSD), while the rest used black market LSD.  The outcomes measured were:

• Post-acute: assessed weekly during the dose period on Sundays, when no capsule was taken. Measures were taken 48–72 hr after the last placebo/microdose capsule. Post-acute outcomes were: Warwick–Edinburgh mental well-being scale (WEMWB) (Tennant et al., 2007), Quick inventory of depressive symptomatology (QIDS) (Rush et al., 2003), Spielberger’s state-trait anxiety inventory (STAIT) (Spielberger, 1983), and Social connectedness scale (SCS) (Lee and Robbins, 1995).
• Acute: assessed weekly during the dose period on Thursdays, when either a microdose or placebo capsule was taken. The testing was carried out 2–6 hr after the ingestion of the capsule, while the potential microdose was active. Acute outcomes were positive and negative affect schedule (PANAS) (Watson et al., 1988), visual analogue scale items (drug intensity, mood, energy, creativity, focus, and temper) and cognitive performance.

They found that microdosing DID in fact result in significant improvements in all categories, however the placebo groups also saw improvement, there was not a significant difference between the two in most categories.  Scores were significantly better when the participant believed they had taken a microdose irrespective of what was actually taken (as part of the study the participants had to guess if they had taken a microdose or placebo).

Interestingly though, they did find one significant difference, anxiety was reduced at the end of microdose weeks compared with placebo weeks.  It may also be worth pointing out that even though it didn't rise to the level of statistical significance, the microdose group did improve more than the placebo group on all scales (from baseline to week 5).

So it may be premature to write off microdosing just yet...