For example, unwise business or financial decisions may be made while in a manic phase. Bipolar depression is the depressive phase of manic-depressive illness, in which there are both extreme highs and extreme lows. Bipolar depression symptoms are similar to those of major depression, with certain variations such as excessive sleep and increase in appetite. A less severe type of depression, dysthymia involves long-term, chronic symptoms that do not disable, but keep a person from functioning at 'full steam' or from feeling good. Sometimes people with dysthymia also experience major depressive episodes.
Dysthymia is a milder form of depression that lasts two years or more.
It is the second most common type of depression but because people with dysthymia may only have two or three symptoms, may be overlooked and go undiagnosed and untreated. Seasonal Affective Disorder is a type of depression that follows seasonal rhythms, with symptoms occurring in the winter months and diminishing in spring and summer. Current research indicates that the absence of sunlight triggers a biochemical reaction that may cause symptoms such as loss of energy, decreased activity, sadness, excessive eating and sleeping.