Microdosing, or low-dose treatment of psychedelics such as lysergic acid diethylamide (LSD), has gained popularity in recent years as a potential method for alleviating symptoms of attention-deficit/hyperactivity disorder (ADHD). However, the first-ever randomised clinical trial investigating the pharmacological effects of psychedelics found that microdosing LSD is as effective as a placebo in improving ADHD symptoms.

Several studies have suggested that taking repeated small doses of psychedelic substances like LSD and psilocybin—one-tenth to one-twentieth of a recreational dose that doesn't hinder daily activities—might be beneficial for ADHD symptom management, along with improvements in well-being, cognitive function, and emotional processing.

However, most of these studies were observational and relied on self-reported data, with a significant lack of clinical evidence from controlled trials in patients.

In a study published in JAMA Psychiatry, a team of scientists from Switzerland and the Netherlands set out to evaluate the safety and effectiveness of repeated low doses of LSD in reducing ADHD symptoms in adults.

They conducted a six-week, multicenter, randomised clinical trial with 53 adults aged 18 to 65 who had been diagnosed with ADHD. Participants were randomly assigned to receive either a 20 μg dose of LSD or a placebo twice weekly to assess its impact on symptom reduction.

The study was placebo-controlled and double-blind, meaning one group received a placebo for comparison, and neither the participants nor the researchers knew who was receiving LSD and who was given the placebo.

The researchers found that it was safe to administer a low dose of LSD in an outpatient setting as it is psychologically well tolerated with no recorded severe adverse effects.

The study assessed ADHD symptom severity in participants using both self-rated and observer-rated scales. Baseline assessments were conducted before treatment and the follow-up assessments after six weeks.

On a 54-point scale, where higher scores indicated more severe symptoms, the researchers observed that both LSD and placebo groups reported symptom improvement. The average scores decreased by 7 points in the LSD group and nearly 9 points in the placebo group, a difference not statistically significant to claim the superiority of one treatment method over the other.

Twice-weekly microdoses of LSD were no more effective than a placebo in treating ADHD symptoms. However, the researchers suggest that alternative strategies, such as daily dosing, alternate-day dosing, or titration dosing—gradually increasing the dose in small amounts to find the optimal level without causing side effects—could potentially yield different results.

These findings challenge anecdotal claims and emphasise the necessity of placebo-controlled studies to accurately assess the impact of low-dose psychedelics on psychiatric disorders.

--Sanjukta Mondal