seasonal affective disorder

noun

: depression that tends to recur chiefly during the late fall and winter and is associated with shorter hours of daylight

—abbreviation SAD

Did you know?

Seasonal affective disorder hasn't been recognized as a medical condition for very long, and the term has only become part of the general English vocabulary during the past three decades or so (its earliest documented appearance in print dates from 1983). "Seasonal affective disorder" (abbreviated SAD) is also sometimes called "Winter Depression" and some researchers describe it as a "hibernation reaction" in which sensitive individuals react to the decreasing amounts of light and the colder temperatures of fall and winter.

Examples of seasonal affective disorder in a Sentence

Recent Examples on the Web

Moreover, symptoms of seasonal affective disorder (or SAD, a type of depression related to seasonal changes) do reportedly reach their severity in January and February, according to The Mayo Clinic. —Jamie Cuccinelli, Martha Stewart, 19 Jan. 2026

Because serotonin is produced partially in response to sunlight exposure, shorter days can cause a drop in levels, according to Nguyen—a potential cause of seasonal affective disorder (SAD). —Caroline Tien, SELF, 15 Jan. 2026

The symptoms that social media users are describing might overlap with seasonal affective disorder, depersonalization or the long-term effects of past trauma, Fisher said. —The New York Times News Service Syndicate, San Diego Union-Tribune, 6 Jan. 2026

This is known as seasonal affective disorder (SAD), or seasonal depression. —Marisa McMillan, Outside, 20 Dec. 2025

Word History

First Known Use

1983, in the meaning defined above

Rhymes for seasonal affective disorder

• boarder
• border
• corder
• order
• warder
• camcorder
• recorder
• reorder
• suborder
• transborder

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Medical Definition

seasonal affective disorder

noun

sea·​son·​al affective disorder ˌsēz-ᵊn-əl- 

: depression that tends to recur each year chiefly during the late fall and winter and is associated with shorter hours of daylight

—abbreviation SAD