Seasonal Affective Disorder—or SAD—might be one of the most appropriate acronyms in medical history. It’s a depressive condition that reflects the ultimate battle between light and darkness—sunshine hidden by clouds, and sunsets happening quicker and sooner than ever. As a result, symptoms usually start in the fall, and subside in early spring or summer.

It comes on suddenly, often with little to no warning. You’re minding your own business, attending to errands and going about your day, when suddenly the room starts to spin.