One Dose of An Antidepressant Can Change Your Brain, Study Says

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Depression is an incredibly common mental health disorder — in the U.S., for example, at least 10 percent of adults experience depression. And yet, treating depression remains an incredibly complex, and often ineffective endeavor. Antidepressants can take up to a month to work. Even after this period, there's no guarantee an antidepressant will work on a patient: No one antidepressant works for everyone, so finding one that works can sometimes require trying many antidepressants that do not.

New research into how the most popular class of antidepressants, selective serotonin reuptake inhibitors (SSRIs), impact the brain could one day help practitioners select the most appropriate antidepressant for patients.

This new research, published today in the Cell Press journal Current Biology, suggests that just a single SSRI dose can change connectivity — in very basic terms, how different parts of the brain communicate — within three hours.

The researchers first tracked brain connectivity in medication-free individuals, letting "their minds wander for about 15 minutes in a brain scanner that measures the oxygenation of blood flow in the brain." They used this data to map connections in the brain. Next, researchers administered the group a single dose of escitalopram — the SSRI antidepressant sold under the brand-name Lexapro — and scanned their brains.

They found that this single dose reduced connectivity in most parts of the brain, but increased connectivity within the cerebellum and thalamus — the parts of the brain associated with motor control and signal regulation, respectively — within hours.

"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," Julia Sacher, of the Max Planck Institute for Human Cognitive and Brain Sciences, says in a statement about the research.

Though the study does not indicate exactly how these shifts in connectivity pertain to a drug's function on these areas of the brain, researchers feel that the glimpse into the SSRIs' immediate impact on the brain will aid depression research and treatment. The plan to examine brain connectivity in patients successfully recovering from depression after using SSRIs and compare that data to patients who haven't responded to weeks of SSRI treatment, could help practitioners predict whether a patient should take an SSRI or pursue another therapy, a statement on the study indicates.

"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," Sacher said.