Depression

Depression changes the brain, causing distinct structural alterations visible on brain scans, but effective treatment can eventually make a depressed brain resemble a healthy one.

JJ Schildkraut theorized depression is linked to brain chemical imbalances—in 1965

Schildkraut was one of the first to put forward this idea, which stemmed from lab animal research. A decade later, researchers published the first landmark paper on fluoxetine—better known by trade name Prozac—which increases serotonin levels in the brain.

These areas of the brain are hard-hit in depression—but the changes are reversible

Depressed brains can have certain characteristic changes, including an overactive amygdala, reduced hippocampus size, and changes to the thalamus and neuromodulating chemicals in the brain.

US depression rates at historic high among adults

More than 18% of US adults reported that they currently have or are being treated for depression in both 2024 and 2025. In the 2025 survey, more than 11,000 adults were surveyed. The numbers have ticked upward since 2015—by about 8 percentage points—with most of the increase occurring from the 2020 pandemic onward.

1 in 10 US adults are taking medication for depression

A US government report indicates that about 10% of US adults took prescription medication for this disorder in 2023. Women, at 15.3%, were more than twice as likely to take one of these medications than the 7.4% of men.

'Melancholia' was the ancient Greek term for depression

"Melancholia" in Hippocrates's time was derived from the Greek word for black bile. This term made sense in its context since the Greeks believed that depression stemmed from an improper balance of the four humors.

Teen depression levels jumped during the pandemic

US government data published in 2025 but gathered from August 2021 through August 2023 indicated that depression prevalence among teens aged 12 to 19 was at 19.2%. It was even higher among females of that age group—26.5%

Watch actress Kristen Bell discuss her challenges with depression and anxiety

Bell describes how depression can make it difficult to celebrate good news, and how decision fatigue can make simple decisions feel Herculean. She reveals how she wishes she'd discussed these struggles publicly earlier in her career.

See how antidepressants—used by roughly 1 in 10 Americans—were discovered.

Explore this deep dive into how SSRIs work

This 101-style explainer on selective serotonin reuptake inhibitors explains how they work in the brain—complete with classroom-style whiteboard drawings. It covers common SSRIs, why someone might try this medication, and a deeper discussion about potential side effects.