Major Depression: People who have major depression have had at least one major depressive episode (five or more symptoms for at least a two-week period). For some people, this disorder is recurrent, which means they may experience additional episodes. One of these symptoms has to be a depressed mood or loss of interest or pleasure.
Dysthymia: Is a low-level state of depression that lasts a long time. It is not as severe as major depression, but can be just as disabling. Symptoms of dysthymia include many, sometimes all of the symptoms for depression. Fewer symptoms are necessary to make the diagnosis. With dysthymia, individuals are often able to function better. They might be able to go to work and manage their lives to some degree. They may not even be aware that they have an illness even though they are irritable, stressed or tired most of the time. Many people with dysthymia believe that this is just their personality.
Postpartum depression: A mother’s depression occurring after the birth of her baby.
Seasonal depression: A major depression occurring regularly in seasons with little sunlight.