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April 23, 2025
Background:
Stimulants, such as methylphenidate and amphetamines, are currently considered effective medications for treating ADHD. However, approximately one-third of patients do not have an adequate response to these treatments. Additionally, long-term adherence is relatively low, with only about half of the patients still using methylphenidate after six years.
Recently, there has been increasing attention to the concept of microdosing with psychedelic drugs such as psilocybin and LSD. A microdose typically ranges from one-tenth to one-twentieth of a recreational dose and does not produce noticeable perceptual effects or interfere with daily activities.
The Study:
A European research team recently published the findings of the first double-blind, placebo-controlled randomized clinical trial examining the safety and efficacy of repeated low doses of LSD in adults diagnosed with ADHD.
The six-week trial took place at University Hospital in Basel, Switzerland, and Maastricht University, Netherlands. Participants, aged 18 to 65, had clinical diagnoses of ADHD with moderate to severe symptoms.
The team excluded persons with a past or present diagnosis of psychotic disorders, substance use disorders, or other psychiatric or somatic disorders likely to require hospitalization or treatments.
Participants were randomly assigned in a 1:1 ratio to receive either LSD or placebo. Neither study staff nor participants were aware of the assignments until the conclusion of the trial.
During the six-week trial, participants received twice-weekly doses on-site, amounting to a total of 12 doses. Following the first and final doses, participants were asked to determine whether they had been administered LSD or a placebo in order to assess blinding. Four weeks after the conclusion of the microdosing period, participants returned for an evaluation of the treatment's safety and efficacy.
Twenty-seven of the 53 participants were randomized to receive the LSD microdosing treatment in a liquid solution, and 26 to receive placebo. Placebo consisted of the same drinking solution, minus the microdose of LSD.
The average age was 37, and 42% of participants were female. Forty-six of the 53 participants completed the study.
Out of 29 participants, 21 from the LSD group and eight from the placebo group correctly guessed their allocation, totaling 63% overall.
As assessed through the Adult ADHD Investigator Symptom Rating Scale, ADHD symptoms improved by 7.1 points in the LSD group and 8.9 points in the placebo group, with no significant difference between them.
Regarding safety, the LSD group experienced nearly double the adverse events compared to the placebo group. None of the events in either group were classified as serious. The five most frequent adverse events were headache, nausea, fatigue, insomnia, and visual alterations, occurring around three times more frequently in the LSD group than in the placebo group.
The team concluded, “although repeated low-dose LSD administration was safe in an outpatient setting, it failed to demonstrate efficacy compared with placebo in improving ADHD symptoms among adults.”
Conclusion: Microdosing with LSD did not offer significant advantages over placebo in treating ADHD symptoms, despite being physically safe and well tolerated in the trial setting. This suggests that further research is needed to explore alternative treatments for ADHD.
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Struggling with side effects or not seeing improvement in your day-to-day life? Dive into a step-by-step journey that starts with the basics of screening and diagnosis, detailing the clinical criteria healthcare professionals use so you can be certain you receive an accurate evaluation. This isn’t just another ADHD guide—it’s your toolkit for getting the care you deserve. This is the kind of care that doesn’t just patch up symptoms but helps you unlock your potential and build the life you want. Whether you’ve just been diagnosed or you’ve been living with ADHD for years, this booklet is here to empower you to take control of your healthcare journey.
Proceeds from the sale of this book are used to support www.ADHDevidence.org.
Lorenz Mueller, Joyce Santos de Jesus, Yasmin Schmid, Felix Müller, Anna Becker, Aaron Klaiber, Isabelle Straumann, Dino Luethi, Eline C. H. M. Haijen, Petra P. M. Hurks, Kim P. C. Kuypers, and Matthias E. Liechti, “Safety and Efficacy of Repeated Low-Dose LSD for ADHD Treatment in Adults: A Randomized Clinical Trial,” JAMA Psychiatry (2025), https://doi.org/10.1001/jamapsychiatry.2025.0044.
Counting umbilical cord vessels is standard in prenatal ultrasounds and confirmed at birth. Single umbilical artery (SUA) occurs in about 1 in 200 cases, with roughly 10% associated with anomalies, including central nervous system defects. Isolated SUA (iSUA) means one artery is missing without other structural issues.
Research on SUA, especially isolated iSUA, and childhood neurodevelopmental disorders (NDD) is limited and inconclusive. iSUA is linked to preterm birth and small-for-gestational age (SGA), both of which are NDD risk factors.
This Norwegian nationwide population study aimed to assess NDD risk in children with iSUA at birth, the influence of sex, and how preterm birth and SGA mediate this relationship.
The nation’s universal single-payer health insurance and comprehensive population registries made it possible to analyze all 858,397 single births occurring from 1999 to 2013, with follow-up continuing through 2019. Among these cases, 3,532 involved iSUA.
After adjusting for confounders such as parental age, education, and maternal health factors, no overall link was found between iSUA and later ADHD diagnosis. However, females with iSUA had about a 40% higher risk of subsequent ADHD compared to those without iSUA, even after adjustment.
The authors concluded, “The present study indicates that iSUA is weakly associated with ID [intellectual disability] and ADHD, and these associations are influenced by sex. This association is mediated negligibly through preterm birth and SGA. The associations were not clinically significant, and the absence of associations of iSUA with other NDD is reassuring. This finding can be useful in the counseling of expectant parents of fetuses diagnosed with iSUA.”
Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism (distorted vision due to irregular curvature of the eye or lens), are common worldwide. These conditions affect 12%, 5%, and 15% of children, and rise significantly in adults to 26.5%, 31%, and 40%. Additionally, strabismus (misalignment of the eyes) and amblyopia (reduced vision in one eye from uneven image formation, often linked to strabismus) occur globally at rates of 2% and 1.4%, respectively.
Visual impairment can affect children’s concentration in school, and studies suggest a link between eye disorders and ADHD.
To investigate this relationship, two researchers – one based in the US and the other in Israel –carried out a nationwide retrospective cohort study using electronic medical records of all insured individuals aged 5 to 30 who were part of Maccabi Health Services, Israel’s second largest health maintenance organization, between 2010 and 2022.
Of over 1.6 million insured members (2010–2020), inclusion/exclusion criteria and propensity score matching for age and sex were applied, along with a one-year wash-out period between the first eye diagnosis and ADHD diagnosis. In total, 221,707 cases were matched with controls without eye disorders at a 1:2 ratio, resulting in a cohort of 665,121 participants.
Overall, those with any previous eye diagnosis were 40% more likely to have a subsequent ADHD diagnosis. This was slightly higher for females (45%) than for males (35%). It was also slightly higher for children and adolescents (42%) than for adults (37%).
More specifically:
The authors concluded that eye disorders are associated with ADHD. They noted these associations were more marked in females and children and adolescents, although, as noted above, those differences were small. They recommended that primary care providers and neurologists consider risk stratification for early screening, and that ophthalmologists refer high-risk patients for ADHD evaluation.
Acid-suppressive medications, including proton pump inhibitors (PPIs) and histamine-2 (H2) receptor antagonists, are often prescribed during pregnancy to treat heartburn and gastroesophageal reflux disease.
Research shows changes in the gut microbiome can negatively affect neurodevelopment. Since acid-suppressive medications alter gut microbiota, maternal use during pregnancy may impact offspring’s neurodevelopment. Because PPIs and H2 receptor antagonists readily cross the placental barrier, they could potentially influence fetal neurodevelopment.
The link between prenatal exposure to acid-suppressive medications and major neuropsychiatric disorders is not well understood. With the use of these medications during pregnancy rising, it is important to assess their impact on children's long-term neurodevelopment. This study examined whether maternal use of acid-suppressive drugs is associated with increased risk of neuropsychiatric disorders in children, using a large, nationwide birth cohort from South Korea.
South Korea operates a single-payer health insurance system, providing coverage for over 97% of its citizens. The National Health Insurance Service (NHIS) maintains a comprehensive database with sociodemographic details, medical diagnoses, procedures, prescriptions, health examinations, and vital statistics for all insured individuals.
A Korean research team analyzed data from over three million mother-child pairs (2010–2017) to assess the risks of prenatal exposure to acid-suppressing medications. They applied propensity scoring to adjust for maternal age, number of children, medical history, and outpatient visits before pregnancy, to minimize confounding factors. That narrowed the cohort to just over 800,000 pairs, with half in the exposed group.
With these adjustments, prenatal exposure to acid-suppressing medications was associated with 14% greater likelihood of being subsequently diagnosed with ADHD.
Yet, when 151,737 exposed births were compared to the same number of sibling controls, no association was found between prenatal exposure and subsequent ADHD, which suggests unaccounted familial and genetic factors influenced the preceding results.
The Take-Away:
Evidence of these medications negatively affecting pregnancies is mixed, mostly observational, and generally reassuring when these medications are used appropriately. Untreated GERD and gastritis, however, have known risks and associations with the development of various cancers. With no evidence of an association with ADHD (or for that matter any other neuropsychiatric disorder), there is no current evidence-based reason for expectant mothers to discontinue use of acid-suppressing medications.
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