As the days grow shorter, many people may feel an inexplicable shift in their mood. While some of this can largely be attributed to changes in daylight, for others, it signals the onset of Seasonal Affective Disorder (SAD). SAD is more than just feeling "the end of summer/ winter blues." It’s a legitimate form of depression that can impact your daily life. As we enter the holiday season—a time often depicted as joyful and celebratory—SAD can feel even more overwhelming. It’s really important that you understand this condition, along with why it happens and how it’s influenced by more than just the weather.