depressive disorders
Major Depression 
Bipolar Disorder Dsythymia
General Information about Depressive Disorders. Depressive disorders are more than feeling sad or blue. They impact the way one feels about oneself, other people, the future, and the world in general. Depressive disorders come in different forms, and some are characterized by cycling mood changes between severe lows and highs (mania). Please click on the disorders listed above to read a brief description of the symptoms specific to three of the most common types of depressive disorders. You may also find the Depression and Bipolar Support Alliance website to be helpful.
Major Depression. Major depression is characterized by depressed mood, a loss of interest or pleasure in hobbies and activities that were once enjoyed, feelings of hopelessness, excessive or inappropriate guilt, eating and sleep disturbances, fatigue, loss of concentration, and repeated thoughts of death or suicide. The severity, number, and clustering of symptoms vary with each individual.
Bipolar Disorder. Bipolar disorder, also known as manic-depressive illness, is characterized by cycling mood changes between extreme lows and highs. Some people, however, may experience manic phases without suffering from depressed periods. Manic symptoms include a distinct period of at least one week with an excessively elevated mood, irritability, grandiosity, decreased need for sleep, increased talking, flight of ideas, distractibility, excessive risk-taking, and impulsive spending and sexual activity. The severity, number, and clustering of symptoms vary with each individual.
Dysthymia. Dysthymia is characterized by chronic feelings of malaise, general depressed mood, low self-image, little energy, poor appetite or overeating, hopelessness, irritability, and difficulty concentrating and making decisions. These symptoms generally cause less impairment than major depressive episodes but last for at least two years.