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8 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…
Researchers used PET brain scans to compare dopamine reward-system markers in 45 adults with ADHD and 41 adults without ADHD. People with ADHD scored lower on an Achievement scale (a stand-in measure for motivation), and in the ADHD group those lower scores were linked to lower availability of dopamine D2/D3…
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…
The researchers used PET scans with [11C]UCB-J to measure SV2A, a protein that marks presynaptic nerve terminals, and tested whether a single ketamine dose changes synaptic density in the living brain. Overall, they did not find a measurable change in SV2A 24 hours after one ketamine dose in non-human primates,…
Long-term MRI studies show that people with bipolar disorder often have unusual brain changes over time, but the pattern is mixed and not fully clear. Some studies link manic episodes to faster thinning and volume loss in parts of the prefrontal cortex. A large multi-site study (307 patients, 925 controls,…
Researchers pooled results from 29 human studies that measured blood levels of a protein called brain-derived neurotrophic factor, or BDNF, after people received so-called psychoplastogen drugs such as ketamine or psychedelics. They found no clear change in blood BDNF after these drugs. The authors say this does not prove the…
This large South Korean study followed 3,951,398 adults for an average of 11.1 years to compare deaths in people with and without recorded mental disorders. After adjusting for age, sex, health conditions, income, smoking, drinking and physical activity, people with mental disorders had higher rates of suicide and higher overall…
This systematic review and meta-analysis combined 311 clinical studies (653,558 children and 43,311 adults) up to August 1, 2023. It found that ADHD/hyperkinetic disorder occurred in 32.4% (95% CI 31–34%) of pediatric patients and 21.4% (95% CI 20–23%) of adult patients seen in clinical settings — about 8–9 times higher…
