The term “depression” can be used to refer to several mental health conditions, including persistent depressive disorder, bipolar depression, seasonal affective disorder (SAD) and postpartum depression. Persistent depressive disorder is diagnosed when someone has a depressed mood that lasts for at least two years. Their depressive symptoms may improve from time to time, but they never completely go away.
Bipolar disorder isn’t the same thing as major depressive disorder (MDD), but the two conditions share some of the same symptoms. People with bipolar disorder typically experience episodes of depression and mania or hypomania. The depressive episodes cause symptoms similar to the ones caused by MDD, including depressed mood, lack of interest in regular activities, appetite changes, fatigue and inability to concentrate.
People with SAD typically display depression symptoms in the winter, which is when there’s less natural sunlight available. A lack of sunlight can cause people with SAD to sleep more, withdraw from social activities and gain weight due to a lack of activity.
Postpartum depression occurs following the birth of a baby. Hormonal changes, the stress of caring for a new baby and other factors can cause normal “baby blues” to turn into a more serious case of depression. Women with this condition may experience severe mood swings, appetite changes, insomnia, feelings of hopelessness or recurrent thoughts of death.