Generally, a mood state characterized by a sense of
inadequacy, a feeling of despondency, a decrease in activity or reactivity,
pessimism, sadness, and related symptoms. In this sense depressions are quite
normal, relatively short-lived, and (damnably) frequent. In psychiatry, any of a
number of affective disorders in which the above characteristics of mood are
extreme and intense. Depression in this sense may be symptom of some other
psychological disorder. Note that Anhedonia (general lack of interest in the
pleasures of life) is an essential characteristic of depression.