In a recent breakthrough, scientists found that certain fast-acting antidepressants, like ketamine, magic mushroom compound (psilocybin), and scopolamine, can change the way negative feelings affect memory in rats. This discovery opens up new possibilities for understanding and treating Major Depressive Disorder (MDD), a widespread mental health issue causing persistent sadness and loss of interest.
Major Depressive Disorder is a serious condition affecting how people feel and act, and current treatments often fall short. Researchers have been exploring unconventional options, particularly substances with rapid effects, to tackle this challenge.
Magic mushroom compound psilocybin, ketamine (originally an anesthetic), and scopolamine (used for motion sickness) have caught scientists' interest due to their quick impact on mood disorders. Unlike traditional treatments that take weeks to work, these substances act fast and through different pathways.
The study, led by Professor Emma S. J. Robinson from the University of Bristol, used rats to see how these fast-acting antidepressants affect emotional biases. They found that when given to rats, these antidepressants not only reduced the impact of stress but also made some memories more positive. This is significant because people with depression often remember things in a negative way, contributing to their low mood.
The researchers used a simple test with rats to simulate a negative emotional state. The rats were trained to associate digging in certain places with getting a food reward. Then, the researchers induced stress in some rats and gave them the antidepressants. The results showed that these drugs not only lessened the negative impact of stress but also made some memories feel more positive.
The effects of ketamine and psilocybin were particularly long-lasting, even beyond the time the drugs were active in the rats' bodies. This suggests that these drugs might cause lasting changes in the brain, potentially reversing the negative effects that depression has on memory.
While this study provides valuable insights into fast-acting antidepressants, it's essential to note that it focused on a specific aspect of depression. The researchers acknowledge that more experiments are needed, including studies in humans, to fully understand the effects of these drugs. They are also exploring whether it's possible to develop rapid-acting antidepressants without some of the side effects associated with these substances.
The study, “Rapid-acting antidepressant drugs modulate affective bias in rats“, was authored by Justyna K. Hinchcliffe, Sarah A. Stuart, Christian M. Wood, Julia Bartlett, Katie Kamenish, Roberto Arban, Christopher W. Thomas, Aslihan Selimbeyoglu, Shaun Hurley, Bastian Hengerer, Gary Gilmour, and Emma S. J. Robinson.
Update: View the study in full "Psilocybin-induced default mode network hypoconnectivity is blunted in alcohol-dependent rat"