- The study did not find significant analgesic effects of 15 μg LSD microdosing on pain tolerance or subjective pain perception among healthy participants.
- Post-hoc analyses indicated marginal improvements in pain tolerance and reduced unpleasantness, but only after the first dose, suggesting potential dosage issues.
- A slight correlation was observed between increased blood pressure and pain tolerance within the LSD group, pointing to possible physiological influences on pain perception.
Introduction to the Study
Classic psychedelics, notably those affecting serotonin receptors, have garnered interest for their therapeutic applications, especially in treating conditions like treatment-resistant depression, anxiety, and addiction. Historical accounts from the 1960s suggested potential efficacy for compounds such as lysergic acid diethylamide (LSD) in managing pain, including instances of phantom limb pain and in end-of-life care scenarios. Modern studies have echoed these initial claims, revealing that low doses of LSD may heighten pain tolerance with only slight alterations in consciousness. The concept of microdosing involves consuming very low, non-hallucinogenic amounts of these psychedelics, which has gained traction due to anecdotal support for various health improvements, including pain management. Typically, microdoses are about one-tenth of a standard dose; for LSD, this equates to around 15 micrograms. Despite some research into single doses of this substance and their analgesic effects, systematic investigations into repeated microdosing patterns remained scarce until the present study was conducted.Study Design and Methodology
The researchers aimed to investigate the potential analgesic effects of repetitive microdosing of 15 μg LSD, hypothesizing that such administration would enhance pain tolerance while diminishing feelings of pain, unpleasantness, and stress during a standardized pain-induction protocol. This randomized, double-blind, placebo-controlled study involved two groups of healthy volunteers who received 15 μg of LSD or a placebo twice weekly over a period of two weeks. Each participant took four doses in total.Participants and Interventions
The eligibility criteria for potential participants required fluency in English and a body mass index (BMI) between 18 and 28. Exclusion criteria encompassed those with psychiatric backgrounds, drug dependencies, ongoing psychotropic medications, recent psychedelic use, and certain medical conditions. Out of 53 initially recruited individuals, 48 completed the study, comprising 24 males and 24 females with ages spanning from 18 to 65. The study also ensured that participants received LSD in an ethanol solution, with the placebo consisting solely of ethanol.Outcomes Assessments
Pain tolerance was gauged via the Cold Pressor Task (CPT), which involved submerging a hand in nearly freezing water. Subjective assessments of pain, unpleasantness, and stress levels were collected consecutive to this exposure using visual analogue scales. Additionally, participants reported their subjective experiences of being “under the influence” of the drug during dosing days, while vital signs, including blood pressure and heart rate, were monitored before and after doses.Results Overview
The blood tests confirmed LSD presence in the participants receiving the drug. Despite this confirmation, the full sample revealed no significant enhancements in pain tolerance when compared to the placebo group. A notable percentage of participants reached the test’s maximum limit for pain exposure, resulting in a “ceiling effect” that impeded the detection of differences in tolerance levels. Furthermore, subjective ratings of pain, unpleasantness, and overall stress indicated no significant distinctions between those who received LSD versus the placebo.Blood Pressure Findings and Subjective Experiences
The study did observe slight increases in systolic blood pressure among those taking LSD; however, these levels remained within a normal range. The data suggested a positive relationship between elevated blood pressure and increased pain tolerance in the LSD group, hinting that physiological responses might influence pain management properties of the drug. Participants consistently reported mild, sustained feelings of being “under the influence,” but this sensation did not correlate directly with their pain outcomes.Exploratory Analyses and Findings
After excluding participants categorized as “pain-tolerant”, follow-up analyses of a smaller subset indicated some minor evidence supporting an increase in pain tolerance and a reduction in unpleasantness with LSD application. These effects were mainly seen after the first dose and less pronounced upon subsequent doses, implying that tolerance might develop with repeated use. This finding raises questions about the potential need for different dosing schedules in future studies to optimize pain management benefits.Discussion of Findings
The overall findings revealed that 15 μg of LSD microdosing produced limited and variable effects on pain. While the primary sample exhibited no substantial differences in pain tolerance compared to placebo, the exploratory evaluation of those without high innate pain tolerance indicated slight advantages, albeit inconsistent. Further exploration highlighted a potential relationship between physiological changes, such as increased blood pressure, and pain resilience, albeit without evident strong linkage to heart rate variations.Limitations and Future Directions
The study faced several limitations. Primarily, the Cold Pressor Task was subject to ceiling effects, as many participants maximized their pain exposure durations, subsequently restricting the ability to discern drug effects. Moreover, the choice to conduct the study on healthy subjects rather than those with chronic pain may limit the applicability of the results to clinical settings. The researchers acknowledged that tolerance to microdosing might emerge swiftly and proposed that utilizing varied dosing regimens could potentially yield different outcomes in pain management. Lastly, the authors cautioned against over-interpreting the preliminary results from the smaller subsamples in post-hoc analyses, emphasizing the necessity for replication in larger studies to ascertain the true efficacy of LSD microdosing for pain perception and treatment.See also our coverage of Pharmacokinetics and pharmacodynamics of sublingual, and our explainers on side effects. Read the full paper summary on Blossom.
