Shelly Fan in Singularity Hub:
Depression is like waking up to a rainy, dreary morning, every single day. Activities that previously lightened the mood lose their joy. Instead, every social interaction and memory is filtered through a negative lens. This aspect of depression, called negative affective bias, leads to sadness and rumination—where haunting thoughts tumble around endlessly in the brain. Scientists have long sought to help people out of these ruts and back into a positive mindset by rewiring neural connections. Traditional antidepressants, such as Prozac, cause these changes, but they take weeks or even months. In contrast, psychedelics rapidly trigger antidepressant effects with just one shot and last for months when administered in a controlled environment and combined with therapy.
Why? A new study suggests these drugs reduce negative affective bias by shaking up the brain networks that regulate emotion. In rats with low mood, a dose of several psychedelics boosted their “outlook on life.” Based on several behavioral tests, ketamine—a party drug known for its dissociative high—and the hallucinogen scopolamine shifted the rodents’ emotional state to neutral.
Psilocybin, the active ingredient in magic mushrooms, further turned the emotional dial towards positivity. Rather than Debbie Downers, these rats adopted a sunny mindset with an openness to further learning, replacing negative thoughts with positive ones.
More here.