Will Psychedelics Break the Major Depression Logjam?

With tens of millions of euros in the offing, researchers across the European Union have eagerly taken up the gauntlet to find novel interventions for difficult-to-treat mental health and pain conditions. Their target is psychedelics, including classic compounds like psilocybin and atypical ones like ketamine and MDMA. Some of these still carry a stigma as party drugs and spiritual gateways to holotropic experiences.

A total of 12 groups make up the European College of Neuropsychopharmacology’s psychedelic research network. Along with several affiliates, the groups span nine countries (Denmark, Sweden, Finland, Switzerland, Germany, the Netherlands, the Czech Republic, Greece, and the United Kingdom) and are focused on the use of psychedelic compounds as potential treatments for psychiatric conditions such as treatment-resistant depression (TRD), addiction, attention-deficit/hyperactivity disorder, anorexia, and obsessive-compulsive disorder.

One of the largest endeavors is PsyPal, a 4-year, randomized controlled trial investigating the potential of psilocybin for treating psychological distress in palliative care patients with life-limiting conditions. PsyPal is the first multisite clinical trial funded by the European Union to explore psychedelic-assisted therapy.

At PsyPal’s helm is Robert Schoevers, MD, PhD, professor of psychiatry and Department Head at University Medical Center Groningen (UMCG), Groningen, the Netherlands, a major hub for psychedelic research.

Schoevers is a bit of a pioneer who said he entered psychedelic research somewhat reluctantly. A decade ago, a colleague showed him a few papers on ketamine and depression. Because UMCG has a large population of patients with TRD, he agreed to do a pilot study. Since then, he has put together an interdisciplinary team of 25 researchers, published numerous papers, and currently has seven studies, including PsyPal, in various stages of progress.

Schoevers is also building a large national consortium that aims to investigate and, if shown effective, implement novel psychiatry treatments much more rapidly and efficiently than current drug development and approval processes, which can take 12 years or longer. He has just secured millions in government funding to start this process.

Next year, Schoevers and his team will decide to test either MDMA for posttraumatic stress disorder (PTSD) or psilocybin for depression in a large clinical trial, with the aim of getting a treatment as near to formal registration as possible. This will involve working with the European Medicines Agency and its Dutch counterpart, talking to experts who are familiar with the US Food and Drug Administration’s rejection of Lykos Therapeutics’ MDMA treatment for PTSD, and working directly with patients through the National Patient Alliance. The team is also talking to insurers and pharma companies.

The ultimate goal is to “see if we can build a platform in the Netherlands that would have a European perspective, serve as a point of entry for researchers with good ideas, and [attract] public funding as well as companies who have interesting compounds we think would be worthwhile to study,” Schoevers said.

His multiple endeavors emphasize a transdisciplinary and transdiagnostic approach he has been honing for decades. He and his colleagues are investigating the clinical, psychological, and neurobiological parallels between different treatment- resistant conditions and seeking to understand how contextual factors might influence patients, experiences, and outcomes.

Connecting the Dots

Jens H. van Dalfsen, PhD, a postdoctoral researcher in biological psychiatry, is the principal investigator of another UMCG group looking into the neurobiological mechanisms of major depressive disorder and TRD. His team’s strategy entails an elaborate coordination between the pre-clinical and clinical research settings.

For example, Sarah Massetti, a PhD candidate in biological psychiatry, is using blood samples collected in clinical trials to investigate the molecular mechanisms underpinning the neuroplasticity and immune-modulating effects produced by psychedelic compounds.

Another line of research spearheaded by Rutger Boesjes, a PhD candidate in biological psychiatry, is exploring the interactions between drugs like ketamine and the circadian system and how they might relate to antidepressant responses in animal models. It could be that the timing of administration of these drugs is relevant, he explained.

The Patient Factor

How psychedelics work and in whom is a big question for the UMCG team and across the research landscape.

“When researchers and the general public talk about psychedelics, they frequently refer to how they promote synaptic plasticity and new connections in the brain,” said van Dalfsen. “But traditional compounds also do that. So the ultimate question that we’ve been exploring is whether findings reflect an actual pharmacological effect or if expectancy also plays a role. In other words: How can we explain why psychedelics might or might not be effective in treatment-resistant patients?” he explained.

This is where the connection to the clinical experience becomes paramount and Joost Breeksema, PhD, comes in.

Breeksema divides his time between UMCG research and his role as executive director and co-founder of the Open Foundation, a nonprofit dedicated to advancing scientific psychedelic research. The work he’s doing outside the university is helping to frame the investigations of the wider group.

So far he has conducted two qualitative studies.

One was an off-label study in which patients with TRD were administered esketamine.

The other was a randomized clinical trial in which participants were blinded to a single 10- or 25-mg dose of psilocybin vs a 1-mg psilocybin microdose placebo that is too small to invoke any effects.

A key insight was the degree to which participants were unprepared for the intensity of their experiences, especially with regards to ketamine. Breeksema said the sessions might not have been so intense or negative for some participants had they been informed beforehand to expect the drugs could provoke “quite overwhelming experiences” and had they been accompanied by an experienced guide providing reassurance and support.

The format for the psilocybin trial met part of this criteria. Participants received a micro (placebo), medium, or high dose in a single session accompanied by two trained therapists. They then engaged in two sessions afterward to process their experiences. A single psilocybin experience appeared to be not enough or too much depending on the dose they were assigned and if they had prior experience with the compound.

Trial participants also felt they needed more help making sense of the experience. “This is a common and important theme,” said Breeksema. “Think about it. If you’ve been depressed for 10, 15 years and…you uncover something and break through something that’s been stuck, you need to process it.”

Jeanine Kamphuis, PhD, a psychiatrist and senior researcher at UMCG and one of the trial study co-authors, explained that they want to find a way to identify who will be too overwhelmed by these experiences if the dose should be adjusted or if some time needs to pass between dosing sessions. They also want to spend more time preparing patients for these sessions.

She emphasized that the studies have provided a reality check. “These are not wonder pills or wonder experiences. And in these types of patients, they’re not intended for a personal growth experience,” she said. “You have a patient who is sitting in front of you who seeks therapy and relief from very severe mood complaints, and the suffering is high,” she said, adding that expectancy bias further complicates patient participation and, likely, outcomes.

The Challenges

For all the potential and opportunity that psychedelics may hold for treatment, UMCG’s work has underscored some challenges.

The field of psychedelic research is characterized by methodological issues, explained van Dalfsen, such as blinding, expectancy, and overestimation of treatment effects. When looking at efficacy, “Is it the compound or the expectancy and promise? This is why it’s important to study how the drugs differ from each other in their biological effects and why they are or are not effective,” he said.

The team has also experienced issues with trial recruitment.

Martijn Godschalk, MD, a PhD candidate in psychiatry, has been addressing this problem while working on RESET-TRD, a phase 3, randomized controlled trial comparing an oral esketamine drink with electroconvulsive therapy in patients with TRD.

He’s been coordinating with local university hospitals, general hospitals, and municipal healthcare clinics to meet inclusion criteria and ensure the trial has enough power to demonstrate effectiveness. In turn, these sites are able to participate in a trial they wouldn’t normally be involved in due to lack of resources.

But Godschalk said he was concerned that many patients have gotten wind of the hype surrounding psychedelic treatments within psychiatry — a factor that has contributed to recruitment challenges. “There are a lot of patients who are interested in the non-registered drug and don’t necessarily have an interest in the other [control] arm,” he said.

Despite the challenges, the classic psychedelics such as MDMA and psilocybin “seem to catalyze a psychological process that may be harder to get with regular psychotherapies,” said Schoevers.

He remains cautious, noting there are still unanswered questions, such as who are the best candidates for these drugs and whether they might cause harm in certain patients while benefiting others. “I do think that this is the first time in 20 or 30 years that there is a group of potential treatments that would really make a difference.”

Schoevers received grants and other funding from The Netherlands Organisation for Health Research & Development, Horizon 2020, Horizon 2023, the National Institute of Mental Health (USA), UMCG, Stichting tot Steun VCVGZ, Nationaal programma Groningen, Healthcare Innovation Funds, Janssen Pharmaceuticals, Novartis, Compass Pathways, Clexio Biosciences, and GH research.

Liz Scherer is a health journalist based in the United States.