Mapping consent practices for outpatient psychiatric use of ketamine

History repeating: guidelines to address common problems in psychedelic science

Research in the last decade has expressed considerable optimism about the clinical potential of psychedelics for the treatment of mental disorders. This optimism is reflected in an increase in research papers, investments by pharmaceutical companies, patents, media coverage, as well as political and legislative changes. However, psychedelic science is facing serious challenges that threaten the validity of core findings and raise doubt regarding clinical efficacy and safety. In this paper, we introduce the 10 most pressing challenges, grouped into easy, moderate, and hard problems. We show how these problems threaten internal validity (treatment effects are due to factors unrelated to the treatment), external validity (lack of generalizability), construct validity (unclear working mechanism), or statistical conclusion validity (conclusions do not follow from the data and methods). These problems tend to co-occur in psychedelic studies, limiting conclusions that can be drawn about the safety and efficacy of psychedelic therapy. We provide a roadmap for tackling these challenges and share a checklist that researchers, journalists, funders, policymakers, and other stakeholders can use to assess the quality of psychedelic science. Addressing today's problems is necessary to find out whether the optimism regarding the therapeutic potential of psychedelics has been warranted and to avoid history repeating itself.

Reconsidering "dissociation" as a predictor of antidepressant efficacy for esketamine

RATIONALE

The relationship between subjective drug experience and antidepressant outcomes for ketamine derivatives is poorly understood but of high clinical relevance. Esketamine is the patented (S)-enantiomer of ketamine and has regulatory approval for psychiatric applications.

OBJECTIVES

We examined the relationship between acute dissociation, as measured by the Clinician-Administered Dissociative States Scale (CADSS), and antidepressant efficacy, as measured by the Montgomery-Åsberg Depression Rating Scale (MADRS), for esketamine across the 4-week induction phase of treatment.

METHODS

This post hoc analysis combined data (N = 576) from the TRANSFORM-1 and TRANSFORM-2 clinical trials of esketamine for treatment-resistant depression. Linear mixed models were performed using total MADRS score as the outcome variable with the following independent variables: baseline MADRS score, treatment condition × time interaction, and CADSS × time interaction. To assess whether initial dissociation predicted rapid antidepressant benefit with esketamine, a separately planned regression was performed with day 2 MADRS as the outcome variable with the following dependent variables: baseline MADRS, treatment condition, and day 1 CADSS.

RESULTS

The linear mixed model did not show any effect of a CADSS × time interaction (p = 0.7). Looking solely at the effect of day 1 CADSS on day 2 MADRS revealed that each additional CADSS point was associated with a - .04 [95% CI - .08, - .002] (p = .04) decrease in MADRS score.

CONCLUSIONS

We found no evidence of a clinically significant positive or negative association between dissociation and antidepressant effect for esketamine. Our findings suggest that subsequent inquiry in this area will benefit from improved characterization of drug experiences relevant to therapeutic outcomes.

Arketamine, a new rapid-acting antidepressant: A historical review and future directions

The N-methyl-d-aspartate receptor (NMDAR) antagonist (R,S)-ketamine causes rapid onset and sustained antidepressant actions in treatment-resistant patients with major depressive disorder (MDD) and other psychiatric disorders, such as bipolar disorder and post-traumatic stress disorder. (R,S)-ketamine is a racemic mixture consisting of (R)-ketamine (or arketamine) and (S)-ketamine (or esketamine), with (S)-enantiomer having greater affinity for the NMDAR. In 2019, an esketamine nasal spray by Johnson & Johnson was approved in the USA and Europe for treatment-resistant depression. In contrast, an increasing number of preclinical studies show that arketamine has greater potency and longer-lasting antidepressant-like effects than esketamine in rodents, despite the lower binding affinity of arketamine for the NMDAR. Importantly, the side effects, i.e., psychotomimetic and dissociative effects and abuse liability, of arketamine are less than those of (R,S)-ketamine and esketamine in animals and humans. An open-label study demonstrated the rapid and sustained antidepressant effects of arketamine in treatment-resistant patients with MDD. A phase 2 clinical trial of arketamine in treatment-resistant patients with MDD is underway. This study was designed to review the brief history of the novel antidepressant arketamine, the molecular mechanisms underlying its antidepressant actions, and future directions.