Small open-label trial of low-dose psilocybin for distress in palliative care patients

The question

Can a three-week course of very low daily doses of psilocybin be given safely to people with advanced, incurable illness, and might it ease their psychological distress?

What they did

Researchers at two centres in Ottawa, Canada, enrolled 20 adults with advanced illness and an estimated prognosis of 1 to 12 months who were experiencing severe psychological distress. Everyone knew they were receiving psilocybin; there was no placebo group and no comparison treatment. Participants took oral psilocybin daily for three weeks: 1 mg in week 1, 2 mg in week 2 and 3 mg in week 3. The team tracked side effects, whether people could stick with the schedule, and standard depression, anxiety and demoralization questionnaires.

What they found

Of those screened, 59% enrolled; 17 of the 20 started the intervention and 13 of 17 (76%) finished it. Participants were 40 to 84 years old, 53% were female and 82% had cancer. No serious adverse events were reported, and there were nine mild or moderate adverse events; four people withdrew because their disease progressed or they were not responding. Among the 13 who completed, nine (69%) reported a meaningful overall improvement, eight (62%) had more than a 50% improvement on the Hamilton Depression Rating Scale, seven (54%) had more than a 50% improvement on the Hospital Anxiety and Depression Scale, and nine (reported as 72%) had a meaningful improvement on the Demoralization Scale II.

The fine print

This was an uncontrolled pilot: only 17 people started and 13 finished, everyone knew what they were taking, and there was no placebo or comparison group. Results are reported only for those who completed, so the people who dropped out are not reflected in the improvement figures. The study population was selected and mostly people with cancer, follow-up was short, and outcomes were self-reported or rated on questionnaires. This summary is based on the abstract only.

What it means

Giving small daily doses of psilocybin to people with advanced illness appeared feasible and was not linked to serious harms in this small group, and many participants’ distress scores improved. Because there was no control group, the study cannot show that the drug itself caused those improvements.

Evidence grade: Very low. A very small, single-arm trial with no placebo group and no blinding, so improvements cannot be separated from natural change or expectation.

This summary is based on the study’s published abstract.