This paper discusses why testing psychedelic therapies in clinical trials is more complicated than testing regular drugs. When people take psychedelics like MDMA or psilocybin, they clearly notice the effects, which makes it hard to keep the study ‘blinded’ (where neither patients nor researchers know who got the real drug). The author argues that for therapies combining drugs with counseling, this actually makes sense because the therapy itself is part of how the treatment works, not just a confounding factor. However, for stand-alone drug use, this unblinding is a real problem that makes it unclear whether the drug or people’s expectations caused the improvement.