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12 papers
This umbrella review looked at the best existing reviews and large studies to see if depression is linked to low serotonin or low serotonin activity. Across measures of serotonin in fluids, receptor and transporter studies, tryptophan depletion experiments, and large genetic studies, the evidence was mixed or absent. The authors…
Ketamine has been used as a safe anesthetic for more than 50 years and also works well for pain relief. The active form is S(+)-ketamine and it is mainly broken down into an active metabolite called norketamine. Ketamine blocks NMDA receptors in the brain, which helps explain its special effects…
The researchers created personalized brain circuit scores from both task-free and task-evoked fMRI scans in a large group of people with depression and anxiety. Using a standardized processing method, they measured 41 circuit features across six brain systems and used those measures to define six distinct “biotypes.” These biotypes showed…
Researchers are studying whether brain scans taken before treatment can help pick the best treatment for people with major depression. They found that activity in one brain area (the fronto-insular cortex) at rest might tell who will do better with talk therapy versus medication, while high activity in another area…
This study in rodents and in neuronal cell cultures found that ketamine and its antidepressant metabolite (2R,6R)-HNK rapidly lower neuronally released glutamate in brain regions linked to depression. Using fast glutamate sensors (FAST), isolated synapses, and primary cortical neurons, the authors showed reduced depolarization-evoked glutamate release within 30 minutes after…
This randomized, double-blind, placebo-controlled crossover study gave subanesthetic S‑ketamine to 24 healthy young people while recording fMRI and EEG at rest. After ketamine, fMRI showed less connectivity in the medial prefrontal cortex and more connectivity in left and right intraparietal (parietal) areas of the default mode network. EEG showed more…
In a randomized trial, 98 adults with treatment-resistant depression had brain scans before and 24 hours after a single intravenous infusion of ketamine (0.5 mg/kg) or saline. The researchers measured mean diffusivity (DTI-MD), an MRI-based, indirect marker of microstructural brain change that tends to fall when new synapses or tissue…
Ketamine is a drug that blocks NMDA glutamate receptors and can produce symptoms like those of schizophrenia in healthy people. In this multicenter study the researchers compared resting-state brain scans after ketamine or placebo and looked at key brain networks, the dorsolateral prefrontal cortex (DLPFC), and thalamic sub-nuclei. They found…
This small case series tested group-based ketamine-assisted psychotherapy (G-KAP) with five women in a residential eating-disorder program. Participants got weekly intramuscular ketamine in a group for 4 weeks. Four of five showed clinically meaningful drops in depression scores after the final session, and two of five showed clinically meaningful drops…
This paper looks at studies that use transcranial magnetic stimulation and ketamine together to treat depression that has not improved with usual treatments. It notes that each method can reduce depressive symptoms on its own. Some recent research suggests that giving them together might make the benefits stronger and last…
In 14 people with opioid use disorder who each received a single 10 mg/kg dose of ibogaine, researchers measured blood levels of ibogaine and its metabolites over 24 hours and linked those levels to side effects. They found large differences between people in how fast ibogaine was cleared, and that…
