Seasonal affective disorder is a type of depression whose onset varies over the course of the year – usually appearing during the colder months when there is less light. SAD is sometimes also referred to as seasonal depression, winter depression, or winter blues. Wondering if you might be dealing with seasonal affective disorder? Symptoms include weight gain, craving carbs, fatigue, and oversleeping. Other symptoms also appear, as shown below. The infographic below from Fix.com highlights interesting facts and treatment options for SAD.