A systematic review by the Canadian Network for Mood and Anxiety Treatments evaluated evidence for racemic ketamine in treatment-resistant depression. Single intravenous infusions have Level 1 evidence for efficacy in adults, while multiple or maintenance infusions have only Level 3 evidence. Adverse events include dissociative symptoms and hypertension. Non-IV formulations have Level 3 or 4 evidence. Single-dose IV racemic ketamine is a third-line recommendation; repeated use requires careful case-by-case risk-benefit assessment. Oral and other formulations should be limited to specialists with ketamine expertise at tertiary centers due to limited evidence and risk of misuse.
Serotonergic psychedelics are being reconsidered as potential treatments for major depressive disorder. A Canadian task force systematically reviewed clinical trials from 1990 to 2021 and found that only psilocybin and ayahuasca have been tested in contemporary studies. Two pilot studies of single-dose ayahuasca for treatment-resistant depression showed preliminary positive effects (Level 3 evidence). Small randomized controlled trials of psilocybin combined with psychotherapy for major depressive disorder showed superiority to waitlist controls and comparable efficacy and safety to escitalopram with supportive psychotherapy, with additional trials showing efficacy in cancer-related depression (Level 3 evidence).
A proof-of-concept randomized controlled trial will test whether a 4-week mindfulness-based intervention, added to treatment-as-usual, improves anxiety, emotion regulation, and interoception in 50 postpartum mothers with anxiety disorders. The intervention is adapted from Mindfulness-Based Cognitive Therapy and delivered virtually. Self-report measures will be collected at baseline, post-intervention, and at a 3-month follow-up; resting-state functional MRI will be conducted at baseline and post-intervention. The authors hypothesize improvements in anxiety, emotion regulation, and interoception, along with decreased default mode network and increased salience network connectivity. This is the first study to examine combined psychological and neural effects of mindfulness in postpartum anxiety disorders.