This Collection is the second volume of the Research Topic:
Hallucinogens and Entactogens: Establishing a New Class of Psychotherapeutic Drugs?The last years have seen an increasing interest in research on hallucinogenic drugs like psilocybin and LSD. Similar developments were observed for the entactogen MDMA. During the nineteen fifties and sixties this field was in focus, and relatively broad investigations of psilocybin and LSD were conducted, both in basic and clinical research. In this era, psychiatry placed high hopes on these compounds, especially as possible treatment options for various mental diseases. Indeed, many promising observations were made. However, this development came to a halt 50 years ago, when hallucinogens were classified as schedule-I-drugs.
Now, research continues and the current efforts have been extensive. It seems that we are truly experiencing a revival of the classic hallucinogens psilocybin and LSD. Furthermore, related substances like ibogaine and ayahuasca are investigated systematically for the first time and this is also true for the therapeutic use of MDMA. The present research covers pharmacology, genetics and neuroimaging, but also clinical investigations of potential beneficial effects in mental disorders like anxiety, depression, post-traumatic stress disorder, and addiction. Previous findings suggest that a few administrations of these substances might improve symptoms of these disorders in an enduring way, outlasting the acute pharmacological effects by far. It is often assumed that the underlying mechanisms are similar to those which are effective in psychotherapy. This mechanism of action would be unique in psychopharmacology, constituting a new class of psychotherapeutic drugs.
The potential therapeutic applications have become the focus of attention in the public and the scientific community. Although psychiatry has progressed greatly during the twentieth century, there are still patients who do not respond well to established interventions and are therefore considered treatment-resistant. Moreover, psychopharmacological treatments are often accompanied by side effects, posing a challenge for compliance. Genuine innovations have been rare in psychiatry during the last decades. The path from bench to bedside is difficult and new approaches often fail to show clinical efficacy.
In comparison, there is already considerable experience with hallucinogenic and entactogenic substances, and previous findings are promising. However, research in this field is still in its infancy and many questions remain open. For example, it still remains to be resolved if previous, encouraging results can be replicated, which patients might benefit from these treatments and which might not, how therapeutic effects can be promoted and risks minimized.
Larger studies are on their way to address some of these questions. In this Research Topic we encourage original research, reviews, clinical case studies, clinical trials, opinions, hypothesis, perspectives, and technology reports from international researchers and clinicians in this field. We hope that this Research Topic will contribute to close some knowledge gaps in this exciting field of psychiatry.
