Spring fever

Spring fever is a term applied to various mood, physical, or behavioral changes, which may be experienced coinciding with the arrival of spring. It is not a medical term, and is not considered a disease or malfunction of the human body.

The term "spring fever" is an auto-antonym (a term with multiple and opposed meanings):

On the one hand, the term may refer to an increase in energy, vitality, and sexual appetite, as well as a feeling of restlessness, associated with the end of winter. This concept may have a biological basis. A lift in mood with the arrival of spring, and longer periods of daylight, is often particularly strong in those suffering from seasonal affective disorder (SAD), who experience lows or depression during the winter months. It is this sense that inspires the use of the term as a title for several works of literature and entertainment.

On the other hand, the term may sometimes be used to describe an opposite effect of springtime lethargy or depression.

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