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A new discovery: Immediate antidepressants – how do they work?
18.01.2024 08:50
Updated: 13.05.2024 21:21
Some antidepressants work quickly and have long-lasting positive effects on the mood of people with major depressive disorder.
However, we don't fully understand how these effects happen.
A recent discovery shows that all three drugs can modify emotional biases related to learning and memory.
A new study
Negative emotional biases are a key aspect of depression, influencing how the brain processes information and contributing to prolonged low mood.
The study used a test to measure emotional biases in rats and discovered that all treatments reduced negative biases associated with previous experiences.
Ketamine and COMP360 psilocybin showed additional characteristics that could explain their long-lasting effects after a single treatment.
The sustained effects are likely due to changes in brain circuits controlling emotional biases and memory of past experiences.
The drugs specifically targeted emotional biases and affected the prefrontal cortex, a brain region influencing mood.
The experiment suggests that these drugs alter emotional biases linked to past experiences, possibly explaining their rapid mood improvement in patients.
Using an animal model, the study investigated the drugs' effects on learning, memory, and neural plasticity.
A two-stage model was proposed to explain the findings.
In the experiment, rats associated digging materials with rewards under different treatment conditions.
Ketamine, scopolamine, and psilocybin prevented retrieval of negative emotional biases induced in the model.
After 24 hours, low doses of ketamine and psilocybin led to a re-learning effect, where negative memories gained a more positive emotional valence.
Psilocybin also positively influenced new experiences, unlike ketamine or scopolamine.
More research is needed
Further analysis of ketamine's re-learning effects revealed protein synthesis dependence, localization to the prefrontal cortex, and modulation by cue reactivation, aligning with predictions of experience-dependent neural plasticity.
These findings propose a neuropsychological mechanism that may explain the immediate and lasting effects of rapid-acting antidepressants, linking neural plasticity with mood improvement.
Previously, we talked about high-functioning anxiety.
