Effects of Psychedelic Microdosing versus Conventional ADHD Medication Use on Emotion Regulation, Empathy, and ADHD Symptoms in Adults with severe ADHD symptoms: A Naturalistic Prospective Comparison Study

Introduction

Attention deficit hyperactivity disorder (ADHD) is marked by inattention, hyperactivity and impulsivity, and many adults with ADHD also experience difficulties with emotion regulation (ER). ER includes cognitive reappraisal (reinterpreting emotional situations) and expressive suppression (inhibiting emotional expressive behaviour). Previous work indicates that standard ADHD medications improve core ADHD symptoms but have more limited effects on ER and social functioning; research on empathy in adults with ADHD is sparse. Meanwhile, naturalistic reports and some laboratory work on low doses of psychedelics (microdosing, MD) suggest possible benefits for emotional and social functioning, but no prior study had prospectively examined ER and empathy in adults with severe ADHD symptoms using MD. Haijen and colleagues designed two linked prospective naturalistic studies to address this gap. Study 1 followed adults with a diagnosis of ADHD or with severe ADHD symptoms who intended to microdose, measuring ER and empathy at baseline, two weeks and four weeks after starting MD. Because Study 1 lacked a comparator, Study 2 compared a subsample of participants who used MD only with a treatment-as-usual (TAU) control group of people already using conventional ADHD medication, adding measurement of ADHD symptom severity. The overarching aim was to explore whether self-initiated MD is associated with changes in ER, empathy, and ADHD symptoms over four weeks and to provide initial data to inform potential randomised trials.