- The administration of repeated low doses of LSD was found to be safe and well-tolerated among participants, showing no significant adverse effects that would impact the continuation of the trial.
- Microdosing LSD did not demonstrate a statistically significant advantage over placebo in improving ADHD symptoms, with both groups reporting comparable improvements based on standardized rating scales.
- The study’s high placebo response rate suggests that the perceived benefits from LSD microdosing in prior anecdotal reports might largely stem from the participants’ expectations rather than the drug’s efficacy.
Introduction to ADHD and Microdosing
Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder affecting around 2.6% of adults globally. Characterized by symptoms that include inattention and hyperactivity-impulsivity, ADHD can lead to significant impairment in daily functioning. Many affected individuals often experience additional psychiatric disorders. Traditional treatments such as stimulant medications (methylphenidate and amphetamines) and non-stimulant options (like atomoxetine) are common and usually effective in the short term. However, approximately 20-40% of patients fail to respond adequately, and potential side effects lead to early treatment discontinuation. Research indicates that long-term adherence is problematic, with around half of patients stopping methylphenidate therapy after six years. In recent years, the practice of microdosing psychedelics has emerged as an alternative strategy. It involves administering very small doses of psychedelics, such as LSD or psilocybin, generally constituting one-tenth to one-twentieth of a recreational dose. This method aims to improve well-being and cognitive function without inducing significant perceptual alterations or impeding daily activities. Past surveys and observational studies indicate a positive impact on various conditions, including ADHD, leading some individuals to microdose as a form of self-treatment, with common protocols suggesting doses between 5 to 20 micrograms every few days over several weeks.Study Overview and Methodology
In their clinical trial, the authors conducted a 6-week, double-blind, placebo-controlled study across two sites: University Hospital in Basel, Switzerland, and Maastricht University in the Netherlands. The study involved adults aged between 18 to 65 years who had a prior ADHD diagnosis and moderate to severe symptoms, determined by established rating scales. Exclusions included participants with ongoing psychotic disorders or other conditions that could interfere with the treatment. Prior to the study, subjects were required to stop any ADHD or psychiatric medications at least five half-lives before their first visit. They were divided evenly to receive either a dose of LSD (20 micrograms) or a placebo, dosed twice a week for six weeks, totaling 12 doses supervised on-site. Initial doses required a six-hour monitoring period to observe acute effects, while subsequent doses permitted immediate departure after administration. Follow-up checks were scheduled during week 10 to evaluate ongoing efficacy and safety.Outcome Measures and Results
The primary outcome was the change in ADHD symptoms measured by the Adult Investigator Symptom Rating Scale (AISRS) from baseline to week 6. Secondary measures encompassed self-rated assessments using the Conners’ Adult ADHD Rating Scale (CAARS) and the Adult ADHD Self-Report Scale (ASRS). Safety was closely monitored, with regular assessments on vital signs, lab tests, and any adverse events reported. Participants’ subjective experiences were also recorded through Visual Analog Scales and other standard instruments. Within the study’s 53 participants, the mean age was 37 years, with 42% being female. While eight participants dropped out (four from the LSD group and three from the placebo group), both groups reported improvements in ADHD symptoms; however, the differences between LSD and placebo were not statistically significant. The LSD group showed a mean improvement of -7.1 points on the AISRS, whereas the placebo group improved by -8.9 points, highlighting a stark similarity in outcomes.Discussion and Conclusions
This study represents a novel investigation of low-dose LSD administration in adults diagnosed with ADHD. Although it proved to be safe within an outpatient framework, there was no evidence of superior efficacy compared to a placebo in alleviating ADHD symptoms. The notable response rate in the placebo cohort aligns with historical findings on ADHD treatment efficacy and emphasizes the essential role of controlled studies in assessing the potential advantages of low-dose psychedelics. While the authors noted certain limitations, such as the trial’s insufficient power to identify small effect sizes, concentrated enrollment at one site, and the fixed dosing schedule—potentially not reflective of individual reactions—these did not fully account for the negligible performance difference between treatments. Consequently, the researchers suggest that prior observed benefits from psychedelic microdosing might not stem from actual pharmacological effects but rather be influenced significantly by participants’ expectations about the treatment received.See also our coverage of LSD microdosing in major depressive disorder. Read the full paper summary on Blossom.
