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Mental Health

Scientists Have Discovered a New Class of Drugs That Could Actually Prevent Depression


If you or a loved one suffers from depression, anxiety, or post-traumatic stress disorder (PTSD), then you know mental illness isn’t cured by motivational phrases, or by a well-meaning friend’s suggestion to “be thankful for what you have.” Prescription antidepressants save lives, and there’s no shame in taking medication to ease your symptoms. But a new class of drugs now in development may help prevent depression from developing in the first place. Sound too good to be true? Read on.

Most scientists will tell you there’s no way to prevent mental illness, but Rebecca Brachman, PhD, neuroscientist and TED Fellow, is working to change that. In 2019, Brachman gave a TED Talk introducing a new class of drugs that she and a colleague discovered, which they named “alexigents.” They believe this new type of medication could eventually inoculate people against the negative effects of trauma and reduce the prevalence of depression in society. 

The Discovery of Alexigents 

Brachman – a Jacobs Institute Runway Fellow at Cornell Tech supported by Schmidt Futures – and her colleague discovered the drug’s unique effects in 2014. They gave a set of mice a rapid-acting antidepressant, then checked to see if the drug had any long-term effects. Seeing that it had none, they moved on to a new experiment and used some of the same mice.  

During the test, Brachman and her colleague introduced a stressor to the mice that normally causes depression. That’s when something amazing happened: The mice that had been in the previous experiment (and received the rapid-acting antidepressant) didn’t develop depression at all.  

“At first, I thought the stressor just didn’t work, but when I dug into the data, it worked as expected — except for one group,” Brachman told TED Ideas. “It was as though those mice were protected against the stress they’d experienced.” 

Brachman realized that the finding was revolutionary, as this drug could eventually prevent depression caused by stress. She called the drug an “alexigent,” inspired by the Greek term “alexo,” which means “to protect.”  

How Alexigents Work

As Brachman noted in her TED Talk, trauma and extreme stress can easily induce depression and PTSD. “Today, one in five soldiers develop depression or post-traumatic stress disorder or both. But it’s not just soldiers that are [at] high risk for these diseases,” she said. “It’s firefighters, ER doctors, cancer patients, aid workers, refugees, anyone exposed to trauma or major life stress.”  

With so many people at risk for developing mental illness, finding new treatment methods is crucial. Current medications, Brachman pointed out, only suppress symptoms. That’s what makes alexigents so extraordinary.  

“These preventative psychopharmaceuticals are not anti-depressants,” Brachman explained. “They’re a whole new class of drug. And they work by increasing stress resilience – so let’s call them resilience enhancers. 

“Stress resilience is the active biological process that allows us to bounce back after stress, similar to if you have a cold and your immune system fights it off. And insufficient resilience in the face of a significant enough stressor can result in a psychiatric disorder, such as depression. In fact, most cases of major depressive disorder are initially triggered by stress.” 

Brachman’s “resilience enhancers,” or alexigents, may reduce stress in more ways than one. For instance, they may protect against stress hormones and psychological stressors, like bullying, abuse, and isolation. This new class of medications would not prevent traumatic experiences from happening. However, it would help people overcome those experiences and not fall prey to mental illness.  

It may take quite some time before alexigents are available by prescription, depending on FDA approval and market challenges. Pharmaceutical companies may be reluctant to manufacture alexigents, because they are a one-time-use drug that could put lifelong antidepressants out of business.

Still, Brachman strongly believes these drugs are worth fighting for. “The drugs that we’ve discovered open the possibility of a whole new field: preventative psychopharmacology,” she said. “But whether that’s 15 years away, or 150 years away, depends not just on the science, but what we as a society choose to do with it.” 

Watch Brachman’s TED Talk below.  

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