A Single Dose of Antidepressants Changes Your Brain

It turns out that antidepressants may be changing your brain. Scientists have found that a single dose of antidepressant is enough to produce dramatic changes in the functional architecture of the human brain.

In this case, the researchers focused on a commonly prescribed SSRI (serotonin reuptake inhibitor). While SSRIs are among the most widely studied and prescribed form of antidepressants worldwide, it's still not entirely clear how they work. However, they're believed to change brain connectivity in important ways over a period of weeks rather than hours.

That's why researchers decided to look at the brain activity a bit more closely. Participants in the study allowed their minds to wander for about 15 minutes while their brain was being scanned. The scan itself measured the oxygenation of blood flow in the brain. Then, the researchers characterized three-dimensional images of each person's brain by measuring the number of connections between small blocks known as voxels and the change in those connections with a single dose of escitalopram. In the end, the scientists found that one dose of the SSRI reduces the level of intrinsic connectivity in most parts of the brain. It also increases connectivity within the cerebellum and the thalamus. Not only that, but this appears to happen over hours rather than days.

"We were not expecting the SSRI to have such a prominent effect on such a short timescale or for the resulting signal to encompass the entire brain," said Julia Sacher, one of the researchers, in a news release. "The hope that we have is that ultimately our work will help to guide better treatment decisions and tailor individualized therapy for patients suffering from depression."

The findings represent an essential step toward clinical studies in patients suffering from depression. Currently, the researchers hope to compare the functional connectivity signature of brains in recovery and patients who fail to respond after SSRI treatment.

The findings are published in the journal Current Biology.