Depression is a medical condition that negatively affects how a person thinks, feels, and functions. It could be likened to a lead weight that makes every action in life more challenging. Formally diagnosed as major depressive disorder, this persistent feeling of sadness often also includes anhedonia—the inability to feel pleasure in things that once fueled joy. A paradox of depression is that it often robs patients of the energy and motivation to take actions that might make them feel better, including exercising or going out to see friends.
This disorder has been recorded for centuries, dating back to the second century BCE in Mesopotamia, when it was viewed as a spiritual problem. Hippocrates later called it "melancholia," derived from the Greek for "black bile"—a nod to the bodily humor imbalance that he believed explained the condition.
A mix of therapeutic approaches—exercise, medication, meditation, and therapy—can help treat this very common mental health disorder. Roughly 1 in 10 US adults take medication for depression. Recent estimates suggest more than 18% of US adults and teens have depression. Diagnosed rates remain higher among females than males.
If you or someone you know are considering suicide, please call, text, or chat "988" to the 988 Suicide and Crisis Lifeline.
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This video explores the neurobiology of depression and why unraveling the complexities of this disease and its etiology will potentially improve treatments. Effective depression treatment, as this video highlights, can eventually make a depressed brain look like a healthy one on brain scans.
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.
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.
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.
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" 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.
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%
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.
The decadeslong journey to the three major types of antidepressants began with medications designed to treat other maladies. Watch to learn more about how attempts to treat tuberculosis and blood pressure disorders led to new insights about neural chemistry and mood.
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.
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