Back in January, we reported on a story about ketamine’s potential to help fight depression. Now, a new study has revealed exactly how the drug’s antidepressant effects work.
One of the advantages of ketamine as an antidepressant is the fact that its effects kick in within hours after administration. By contrast, common antidepressants can take several weeks to work. With that said, ketamine can only be administered for a limited amount of time because of its many side effects, which include blurred vision, nausea, insomnia, and addiction.
The new study from Northwestern Medicine reveals exactly why ketamine is so quick-acting. The findings provide new insight into how the drug may be adapted as a rapid antidepressant minus the side effects.
How does ketamine work?
The study in mice showed that ketamine is so fast-acting because it increases the activity of a very small number of newborn neurons, which are created as part of a process called neurogenesis. While neurogenesis is most crucial during an embryo’s developmental stage, it continues in some parts of the brain throughout the rest of its life as well.
These new neurons typically come about at a very slow pace. There is evidence that generally increasing the number of neurons leads to changes in behavior. In fact, some antidepressants work by increasing the rate at which new neurons are created. This, however, takes up to a few weeks to happen.
Conversely, ketamine leads to behavioral changes simply by ramping up the activity of the existing neurons. This process can happen almost immediately after the cells are activated by ketamine.
“We narrowed down the population of cells to a small window that is involved,” said lead study author Dr. John Kessler, a professor of neurology at Northwestern University Feinberg School of Medicine. “That’s important because when you give ketamine to patients now, it affects multiple regions of the brain and causes a lot of adverse side effects. But since we now know exactly which cells we want to target, we can design drugs to focus only on those cells.”
According to Kessler, the ultimate goal is to create an antidepressant that doesn’t take weeks for its effects to kick in because that time can be crucial. “If you are badly depressed and start taking your drug and nothing is happening, that is depressing in itself. To have something that works right away would make a huge difference.”
Beyond treating depression
A growing body of research shows that when properly administered, ketamine can also have mental health benefits beyond treating depression. It can also be used to treat psychiatric disorders like anxiety, post-traumatic stress disorder, obsessive-compulsive disorder, as well as alcoholism.
Source study: Nature Communications — Ketamine activates adult-born immature granule neurons to rapidly alleviate depression-like behaviors in mice