Claims that microdoses of psychedelic drugs like LSD or the active ingredient of magic mushrooms bring mental benefits may be due to the placebo effect.
Microdosing is a term for when people regularly take small amounts of drugs such as LSD. Users say it doesn’t get them high, but makes them more creative, sharper or improves their mental health in some way. They may take 10 to 20 per cent of a normal dose, a few times a week.
Some trials suggest larger doses of psychedelics can help relieve anxiety, depression and other mental health conditions. But microdoses have been tested only in small, placebo-controlled trials, with mixed results. The placebo effect is when people gain physical or mental benefits from medical treatments due to the power of expectation.
Because it is hard to get permission for research where people are given illegal drugs, Balázs Szigeti at Imperial College London and his colleagues came up with an unusual trial design. They used internet forums to contact people who were already frequently microdosing at home using LSD, the magic mushroom compound psilocybin or similar drugs, usually bought online. The researchers didn’t analyse the difference in effects based on the drugs participants were using.
Participants were sent empty medical capsules in the post that they could open to insert a small piece of drug-impregnated paper. When reclosed, the loaded pills looked the same as empty ones. The 191 volunteers put the drug into some of their capsules, then put them in batches into envelopes printed with QR codes and shuffled the envelopes so they no longer knew which contained the drugs.
A third of the participants took only the drug microdoses for four weeks, one third got placebo capsules and another third got half and half. The volunteers shouldn’t have been able to tell from the envelopes what they were taking, but the researchers could find out, by analysing the QR codes at the end of the trial.
The volunteers also took objective online tests to measure mental acuity and answered subjective questionnaires about their mood and experiences, as well as recording their guesses as to whether they had taken the drug or placebo.
All three groups experienced similar improvements in their long-term psychological and cognitive outcomes over the four weeks.
People who took the real drugs showed “incredibly small” benefits in their survey answers about mood and creativity in tests done a few hours after dosing, says Szigeti, but only on the subjective tests. There was no benefit seen in the objective tests.
In addition, these effects were most pronounced in people who were good at guessing if they had had the real drug, probably due to a mild noticeable effect, suggesting even these small benefits could have been due to the placebo response, says Szigeti.
But the trial may not be the final word on microdosing, partly because the volunteers weren’t supervised by clinicians.
Bernhard Hommel at Leiden University in the Netherlands says the trial also may have found more of an effect if the researchers had measured people’s creativity using objective tests, rather than simply asking people if they felt creative. “Everyone says that about microdosing and that’s what we as scientists want to know.”