In terms of diagnosis, seasonal affective disorder is not really a separate mood disorder from major depression or bipolar disorder. Instead, “seasonal pattern” is a specifier used as additional diagnostic information to describe the regular pattern of the depressive episode associated with major depression or bipolar disorder. For instance, a person could receive the following diagnosis:
Major Depressive Disorder, Recurrent Episode, Moderate, With Seasonal Pattern
However, since people often refer to this type of depression as “Seasonal Affective Disorder” or “SAD” we will use that terminology here. SAD is a condition that affects a person during specific times or seasons of the year. Typically the depressive symptoms of this condition begin during fall or winter, and end when spring arrives. At other months during the year a person’s mood will be normal, or at least will not meet criteria for clinical depression.
Those who have SAD may notice that in the winter months they have a lack of energy or feel sluggish, they sleep more than usual, they overeat and gain weight, and they may have a craving for carbohydrates. Of those who have SAD, 60%-90% are women. Rates of SAD are higher in those who live at higher latitudes. It also occurs more frequently in younger people and often begins in a person’s twenties.
Diagnosis of a Seasonal Pattern Specifier
Summarized from the Diagnostic and Statistical Manual of Mental Disorders- Fourth Edition, Text Revision
This specifier may describe the depressive episode in major depression or bipolar disorder.
A. A person has experienced a regular pattern of depressive episodes that begin at specific time of the year (e.g., fall or winter), and which are not related to specific yearly stressors such as school/college or seasonal unemployment.
B. The depression also ends or changes at a specific time of the year (e.g., spring).
C. The pattern has occurred for the most recent two years with no other symptoms outside of the pattern.
D. A person has had more seasonal depressions than non-seasonal depressions in his/her lifetime.