The study is a follow-up to one published in 2016, also in the Journal of Psychopharmacology, for which psilocybin was administered to 29 people with cancer to help with psychological distress related to having cancer, such as depression, anxiety, and a sense of hopelessness. The new study is the first to assess the duration of benefits associated with the drug. The 2016 study garnered headlines when it showed that a single dose of psilocybin, combined with nine psychotherapy sessions, led to reductions in anxiety and depression, improved spiritual well-being and quality of life, and improved attitudes toward death in people being treated for cancer. The new study reassessed those patients at three years and four and a half years following the original psilocybin treatment. Of the original 29 participants, 16 were still alive and 15 participated in the new assessment. Of those, 60 to 80 percent had experienced sustained relief from depression and anxiety. Most also attributed positive life changes to the psilocybin therapy and described it as one of the most meaningful experiences of their lives. “I was completely surprised and shocked that it worked for so long,” says lead investigator Stephen Ross, MD, an associate professor in the department of psychiatry at New York University Langone Health. “The suggestion that a single dose of psilocybin in conjunction with psychotherapy can be associated with possibly five years of not having cancer-associated anxiety and depression is nothing short of astonishing,” Dr. Ross says. RELATED: Will Drinking Mushroom Tea Make You Healthier?

A Life-Changing Experience

Dinah Bazer, a former IT bank programmer and ice-skating coach, was among the study participants. She was diagnosed with ovarian cancer in 2010, and while her treatment was successful, she suffered from severe anxiety over the possibility of a relapse. “I thought I would celebrating when I was done with chemo,” Bazer recalls. “But I discover very shortly afterward that all I could think about was recurrence. When does the other shoe drop? Every time I would have to go in for follow-up, I was very anxious. It pervaded my thoughts. As I approached the two-year mark following treatment, my overwhelming feeling was: I’m not going to get past this.” She was referred to the trial and signed up without any qualms. The impact was immediate, Bazer says. “I had such a wonderful experience. I experienced such incredible love,” she says. “When I came out of this experience, everything was slowed, everything was peaceful, everything was just wonderful — this rosy glow.” While some of those effects have faded, Bazer says her anxiety at having a relapse — or over any health concern — vanished and never returned. She also found that the treatment seemed to help her slow down and enjoy life more. “I went into this with a goal, which was to relieve my anxiety about a cancer occurrence. I feel that has been achieved permanently. I just don’t think about it any more,” she says. “This treatment should be available to anyone in a clinical setting. I would do again right now if I could.” RELATED: Large Study Finds No Link Between Use of Talcum Powder in Genital Area and Ovarian Cancer

A Drug That Appears to Work When Others Do Not

A diagnosis of serious or life-threatening illness often generates severe psychological distress in people, eroding quality of life and even increasing the risk of suicide, Ross says. While several psychiatric medications can provide relief from depression and anxiety, many take weeks or months to work. And antidepressants work for fewer than half of people with cancer, says Ross. “Forty percent of the world’s population will be diagnosed with cancer in their lifetime, and about 40 percent develop clinically significant depression and existential distress,” which refers to a sense of hopelessness and the loss of meaning in life, Ross says. “Those things are associated with poorer outcomes, such as an increase in suicide rates and a decrease in good cancer outcomes,” he explains. Evidence of the psychological impact from psilocybin dates back many decades and has led to recent research on whether controlled use of psilocybin in a therapeutic setting can help people with cancer and other individuals who are terminally ill or faced with a life-threatening illness. How psilocybin works to boost psychological and emotional well-being is not well understood, says Ross. However, other research suggests the drug targets a part of the brain that is activated when people engage in self-reflection. The drug may interrupt tendencies to ruminate and worry. RELATED: Yoga: A Natural Antidepressant

On to Bigger, More Diverse Trials

The existing research on psilocybin was carried out in the context of a very small study. “This is a small sample,” says Ross. “So we have to use extreme caution that the treatment caused [the long-term outcomes]. But it’s promising to consider that it could have.” Researchers are planning larger clinical trials with a more diverse group of people with cancer who are experiencing psychological distress. If research continues to show benefit and safety, the treatment could be used in cancer centers as well as in hospice, Ross says. He has applied for permission from the Food and Drug Administration to move forward with a phase 3 clinical trial on the drug and has applied for a National Cancer Institute grant to advance the research. RELATED: Clinical Trials: Your Top Questions Answered