Ketamine for bipolar disorder. LSD for depression. It’s been a busy month for psychedelic drugs in the laboratory, as several studies showed that these drugs typically used recreationally—and illegally—affect the brain in ways that could make them useful for treating mental illness.
First came a small study in the Archives of General Psychiatry that we covered earlier this month, in which scientists tested 18 patients who on average had tried seven kinds of drugs to treat their bipolar disorder. When the researchers gave them small doses of ketamine—a powerful anesthetic that people use recreationally for the hallucinogenic side effects—the patients’ depressive symptoms lessened within a matter of minutes.
Compared to placebo, patients showed significant improvement in mood within 40 minutes of receiving the ketamine infusion, using a common depression rating scale. Symptom improvement peaked two days after the injection, but remained significantly greater than for placebo for three days. Seventy-one percent of the patients responded to ketamine, meaning they had at least a 50 percent improvement in their depressive symptoms. Six percent responded to placebo [Reuters].
Doctors found those results remarkable, because typical antidepressant drugs can take weeks to kick in. Last week saw a separate study that tried to unravel just what ketamine was doing in the brain to create such a fast response. In Science, a team led by Ron Duman tested the drug on rats, and found that its M.O. is enhancing communication in the brain.
“Ketamine… can induce a rapid increase in connections in the brain, the synapses by which neurons interact and communicate with each other, ” Duman says. “You can visually see this response that occurs in response to ketamine.” More specifically … ketamine seems to stimulate a biochemical pathway in the brain (known as mTOR) to strengthen synapses in a rat’s prefrontal cortex—the region of the brain associated with thinking and personality in humans. And the ketamine helped rats cope with the depression analog experience brought on by forcing the rodents to swim or exposing them to inescapable stress [Scientific American].
Writing in Nature Neuroscience Reviews, Franz Vollenweider and Michael Kometer argue that the growing body of research suggests we should change how we think not just about ketamine, but also about psychedelic drugs like LSD and even the active ingredient in magic mushrooms—they all could have something to offer serious medicine.
Mental illnesses such as depression are a growing health problem around the world and Vollenweider and Kometer said many patients with severe or chronic psychiatric problems fail to respond to medicines like the widely-prescribed selective serotonin reuptake inhibitors, or SSRIs, like Prozac or Paxil [ABC News].
The two authors argue that it would be possible to take advantage of psychedelics’ therapeutic benefits if they were given by doctors in controlled amounts. But using illegal drugs in medicine comes with huge legal and political hurdles, as any medicinal marijuana advocate knows. So scientists are already working on the best of both worlds: trying to develop drugs that mimic ketamine or LSD’s effects on the brain without all the hallucinogenic side effects.
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Image: Wikimedia Commons