British Columbia

As psychedelic therapy goes mainstream, former patient warns of danger of sexual abuse

Meaghan Buisson agreed to take part in a clinical trial on the use of MDMA for treating post-traumatic stress disorder after what she calls a “year of darkness.” She says she was not warned about the documented dangers of sexual exploitation.

Meaghan Buisson has alleged she was sexually assaulted by her therapist during MDMA clinical trial

Meaghan Buisson, now an instructor with Outward Bound Canada, began a clinical trial for the use of MDMA to treat PTSD in 2015. (Tony Hoare)

Meaghan Buisson agreed to take part in a clinical trial on the use of MDMA for treating post-traumatic stress disorder after what she calls a "year of darkness." 

She was homeless in Vancouver and out of treatment options as she confronted the aftermath of sexual abuse and assault.

"It was a Hail Mary. It was like, well, what do I have to lose, really?" Buisson, now an instructor with Outward Bound Canada, recalled in an interview with CBC News.

In early 2015, Buisson embarked on a Phase II clinical trial sponsored by the Multidisciplinary Association for Psychedelic Studies (MAPS). Court documents show that her co-therapists were a married couple living on Cortes Island near Campbell River — Richard Yensen, an unregulated psychotherapist, and psychiatrist Dr. Donna Dryer. 

"What I had been told was that psychedelics open you up and there's deep healing," Buisson said. 

"There was no mention ever of the risks of sexual abuse."

But there's a documented history of sexual violation within psychedelic therapy, and Buisson has alleged that Yensen took advantage of her vulnerability to do the same.

She believes there is potential for psychedelics to be healing and says they may have a place in the health-care system, but the risk of serious harm means safeguards are essential. That includes stronger oversight of clinical trials, better measures to prevent abuse and strict regulations for who can provide psychedelic therapy — or, for that matter, any type of psychotherapy.

MDMA is one of several illicit drugs currently being studied for potential uses in psychotherapy. (U.S. DEA/Handout via Reuters)

MDMA, also known as ecstasy, is a recreational drug that produces feelings of euphoria and enhances sensation and sexuality. It's one of several illicit substances, including ketamine, LSD and psilocybin mushrooms, that's currently being studied for potential uses in psychotherapy.

These substances are slowly making their way into mainstream patient care. Health Canada has begun granting exemptions for the legal use of magic mushrooms in therapy, and the College of Physicians and Surgeons of B.C. has opened the door for psychiatrists to prescribe ketamine for treatment of depression.

But Lily Kay Ross, an editor at the drug-focused publication Psymposia, who completed a PhD on social responses to sexual violence, cautions that there is a real danger of coercion in this type of treatment because of the power imbalance and the nature of the substances.

"In therapy, people take drugs to alter their consciousness and enter into a boundary dissolving state," she wrote in an email.

"They may report feeling — and even appear — quite lucid, but they are not able to make sound decisions about sexual engagement. And it is a violation of therapeutic trust to engage sexually."

Police investigating allegations of sexual assault

In a civil claim filed in B.C. Supreme Court in 2018, Buisson alleges she was repeatedly sexually assaulted by Yensen, with Dryer's knowledge, while in treatment with the couple. 

Yensen does not deny having sex with Buisson, but in his response to her lawsuit, he accuses her of initiating it, describing her as "a skilled manipulator." He also denies owing her the duty of care inherent in a doctor-patient relationship, suggesting they were merely fellow participants in a research study, albeit with different roles.

The civil claim has since been settled out of court on undisclosed terms, but MAPS has acknowledged that Yensen carried on an "unethical" sexual relationship with Buisson and said Dryer knew but failed to report it to any authorities. The organization has cut ties with both Yensen and Dryer.

Neither Yensen nor Dryer responded to requests for comment.

Psychiatrist Dr. Donna Dryer and psychotherapist Richard Yensen are a married couple who live on Cortes Island in B.C. (

Buisson has also sought accountability in other ways. 

She filed a sexual assault complaint with the Quadra Island detachment of the RCMP, who confirmed for CBC that an investigation is ongoing.

She also turned to the professional regulators, filing a complaint against Dryer with the College of Physicians and Surgeons of B.C., which has yet to be resolved after three years.

No recourse when psychotherapy is unregulated

Finally, because Yensen was described as a psychologist on the website for MAPS Canada, Buisson filed a complaint with the College of Psychologists of B.C. 

But it turns out Yensen is not a registered psychologist in this province, so the college had no power to investigate or discipline him. Officials did, however, ask him to stop calling himself a psychologist online, according to a letter provided to CBC. 

There is no regulatory body governing people like Yensen in B.C. As it stands, literally anyone can call themselves a therapist or counsellor and start advertising their services to British Columbians.

In December, the Federation of Associations for Counselling Therapists in B.C. (FACTBC) submitted a formal application to Health Minister Adrian Dix, calling for urgent regulation of the profession.

But Dix has now rejected that effort, writing in a Feb. 9 letter that the government won't consider regulation of any new health professions until a new oversight body for health professional colleges is in place.

Glen Grigg, chair of FACTBC, described that decision as "tragically out of step with the gravity of Ms. Buisson's experience." In an email, he said lack of regulation was a major factor in what happened to Buisson.

Buisson is disappointed as well.

"Regulation alone is not going to fix the problem. Therapists can be regulated and still be deeply unethical. But the difference is when therapists are regulated and there's oversight and there's a college, patients have some kind of recourse," Buisson said.

'MDMA can make patients more vulnerable to sexual pressure'

The allegations against Yensen and Dryer are not outliers in the field of psychedelic therapy, where sexual abuse has long been acknowledged as a potential risk.

In fact, MAPS founder and executive director Rick Doblin wrote in his PhD dissertation that: "The loving and trusting feelings that can be induced by MDMA can make patients more vulnerable to sexual pressure."

One of the early American proponents for the use of MDMA in therapy, Richard Ingrasci, was permanently barred from practising psychiatry in 1989 after patients came forward to allege he'd sexually abused them while they were under the influence. Psychiatrist Francesco DiLeo of Maryland had been disciplined for similar violations just two years earlier.

In response to Buisson's experience, MAPS issued a statement in 2019 saying that its policies forbid sexual relationships between therapists and their patients, and "there was no prior indication that Richard Yensen or Donna Dryer would violate this policy."

The organization says its lawyers have determined MAPS was not legally responsible for what happened to Buisson, though it agreed to pay her $15,000 for therapy "on a compassionate basis."

Since Buisson's experience, MAPS has formalized a Code of Ethics that makes it clear practitioners must "avoid entering into dual relationships that are likely to lead to impaired professional judgment or exploitation."

Meaghan Buisson says anyone who's thinking about undergoing psychedelic therapy needs to do their research first. (Jonathan Lee)

The organization has not, however, tightened its policies on who can act as a therapist in clinical trials.

Protective measures including a requirement for two therapy providers to work together on each case were already in place when Buisson began treatment with Yensen and Dryer. MAPS still only requires one member of the team to be licensed, and there are still married couples working together, according to a spokesperson.

Buisson is deeply unsatisfied with the response.

"They didn't put the protocols in place to keep the patient safe. After a harm occurred, MAPS has taken no corrective measures to mitigate the harms," she said.

She urges anyone who is considering taking part in psychedelic therapy not to buy into the hype about psychedelics as miracle cures for psychological issues and to understand that there are risks as well. She also recommends bringing along a buddy who will stay sober and make sure the situation is safe.

"This is not a safe situation. What that does for patients is it puts us in a position of responsibility for our own care," Buisson said.

"Go into it with your eyes open and get informed, get educated." 


Bethany Lindsay


Bethany Lindsay is a Vancouver-based journalist for CBC News, currently reporting on health. Questions or news tips? Get in touch at or on Twitter through @bethanylindsay.