Depression, more technically termed major depressive disorder, is the most prevalent reason for disability claims in the United States and each year afflicts 14.8 million American adults, or 6.7 percent of the U.S. adult population, according to the National Institute of Mental Health. The American Psychiatric Association (APA) classifies major depressive disorder within the more general category of mood disorders and uses severity, symptom descriptions, episode duration and frequency to further distinguish between types of depression.
Current and Past Episode Types
To meet the diagnostic criteria for major depressive disorder, a person must have depressed or irritable mood and/or a loss of interest or pleasure in normally engaging activities. The episode must be at least two weeks long, not be due to a medical condition and include at least five of seven characteristics. These are weight loss of 5 percent or more or marked, daily change in appetite; insomnia or hypersomnia (sleeping too much) almost every day; physical restlessness or observable slowing of motor activities; fatigue or energy loss; daily feelings of worthlessness or guilt; difficulty concentrating or making decisions; and thoughts of death or suicide. If the episode is the first in a person's lifetime, it is referred to as a "single" episode. If one or more episodes have occurred in the past, the current episode is termed "recurrent."
Clinical Feature Types
An episode or type of depression can be described as mild, moderate or severe depending upon how it impacts a person's life. Additionally, the APA classifies the type of depression by other factors like whether the current episode has lasted longer than two years ("chronic") or whether depressed mood is the most prevalent symptom ("melancholic"). Similarly, depressive episodes can be categorized as "catatonic" when the person experiences stupor or marked decrease in energy and physical activity. Another more widely known type of depression, "postpartum onset," begins approximately four weeks after a woman has given birth.
Dysthymic Types
Dysthymic disorder is one more type of depression that is less severe than major depressive disorder but generally lasts longer than a major depressive episode. Dysthymic symptoms include depressed mood for at least two years, low self-esteem, appetite and sleep pattern disturbances, low energy, hopelessness and poor concentration. Dysthymic disorder is classified as "early onset" if symptoms begin before age 21 and "late onset" if they begin at age 21 or later.
References
- "Diagnostic and Statistical Manual (DSM-IV-TR);" American Psychiatric Association; 2000
- U.S. National Institute of Mental Health: Depression
