Depression is characterized as a state of low mood and/or loss of interest or pleasure in most previously enjoyed activities. Depression can occur acutely, often in reaction to certain life events, or chronically, for long periods of time, and can have major adverse effects on one’s relationships, work or school life, sleeping and eating habits, and general well-being. Depression can affect an individual’s thoughts, feelings, and actions. A period of depression lasting longer than two weeks, with significant symptoms, is considered Major Depressive Disorder. A more chronic, less severe form of depression is known as Dysthymic Disorder, with symptoms lasting for a minimum of two years.
Bipolar Disorder, once known as Manic Depression, involves one or more manic episodes and one or more depressive episodes. Manic episodes are periods of time with abnormally-heightened energy levels, thoughts, and mood. During a manic episode, an individual may feel euphoric, get little or no sleep, experience pressured or racing thoughts and speech, and may engage in self-destructive or impulsive behavior. Severe manic episodes may also include psychotic-type symptoms such as hallucinations and delusions. Episodes of mania and depression may alternate rapidly, may be separated by periods of normal experience, or may occur simultaneously in a mixed episode.
Seasonal Affective Disorder, or SAD, is a disorder that occurs when a person recurrently becomes depressed during certain times of the year, most commonly during the winter. This may be a result of decreases in natural sunlight and/or changes in body temperature. The symptoms of SAD overlap with those of depression and include: diminished interest in activities, depressed affect, low levels of energy and/or concentration, as well as changes in appetite. Although SAD tends to naturally improve when the climate changes, it may become a problem when it disrupts functioning during its peak time.