Stanford psychiatrists developed a test to help see if you'll respond to antidepressants

The sadness often descended like a curtain - heavy and dark. But even when my depression threatened to cut me off completely from the world around me, I struggled with the decision to take antidepressants. It wasn't just that I'd been taught to believe that "going on meds" was giving up. No, what really worried me was how I'd cope if the drugs didn't work.

A group of researchers from Stanford has created a tool that could help make that decision much easier. It's a two-part test that they say could one day help predict - with striking accuracy - if someone with depression will respond to antidepressants.

That's a huge development.

Millions of people still grapple with the choice to take medication. Millions more never even have the option - in dozens of countries, including the US, the prescription-only pills remain prohibitively expensive or impossible to access in the first place. And a debate is still raging in the scientific communities of many wealthy nations about whether antidepressants are over or under-prescribed in those countries.

The scientists published their results detailing how the test worked on a study sample in October in the journal Proceedings of the National Academy of Sciences.

"I believe [this] is one very important way to transform how we manage depression," Leanne M. Williams, a psychiatrist at Stanford University and one of the authors of the new paper, told Business Insider. "This could help close the gap between the insights we get from our research and the current devastating impact of depression."

How the test works

For starters, the test has only been given to people with diagnosed depression in preliminary study settings so far. Researchers are still at the stage in their work where they're deciphering how well it works and for whom. In other words, you aren't going to see the test popping up at your doctor's office tomorrow. Still, the scientists who designed the test told Business Insider that they plan to start deploying it in limited real-world settings at Stanford University in the next few months.

At its essence, the test looks at two factors in someone with depression.

The first is specific patterns of brain function in one area of the brain that's thought to play a key role in depression, which the researchers measured by showing people images of emotional (angry and sad) faces while they sat in an MRI machine. The second is a history of exposure to stress in one's early life, such as being abused or neglected as a child. Based on someone's "score" on these two measurements - i.e. Did they show high patterns of brain activity when exposed to the emotional faces? Were they exposed to lots of early life stress? - the researchers were able to come up with a predictive snapshot of how well that person might respond to an antidepressant drug like Prozac or Zoloft.

And what they found could change the course of treatment for countless people.

Depressed people who'd experienced high levels of early life stress and who were highly reactive to specific emotional stimuli were more likely to respond well to antidepressants.

In other words, people with depression in the study who revealed that they'd been abused as a child and whose brain scans showed that they were highly reactive to the angry and sad faces were more likely to have a positive outcome on the drugs. The same outcome was predicted for people who'd experienced low levels of early life stress and were also not very reactive to the faces.

On the other hand, depressed people who said they'd experienced high levels of early life stress but did not react much to the faces (or people who experienced low levels of early life stress but were very reactive to the faces) tended to respond poorly to the drugs.

What does this all mean for depressed people who might one day take the test?

Put simply, we don't know yet. But here's what it could mean in the future for someone with depression: Picture a scenario where this person walks into a clinic, takes the test, and finds out she probably won't respond well to antidepressants. Then, she has options: First, she could either go on the drugs anyway and see what happens (the test does not predict the future - depression is complicated and there's still a chance that someone who performs one way on the test might have a different real life experience). Second, she might be encouraged to try a different route of treatment, such as talk therapy.

More studies are needed before this happens, but if the present study's results are any indicator, the future looks bright.

"We would very much like to see these tests evaluated in medical settings more widely," said Williams.