What's the definition of dysthymia?

See below... Dysthymia is a chronic type of depression in which a person's moods are regularly low, dark, or sad on most days for at least 2 years. However, symptoms are not as severe as with major depression. People with dysthymia will often take a negative or discouraging view of themselves, their future, other people, and life events. Problems often seem more difficult to solve.
Dysthymia. Dysthymia, is a chronic type of depression that doesn't waver all that much in terms of intensity, as opposed to major depression which wavers widely in intensity. Metaphorically speaking, those with dysthymia experience it as having to wear a coat made of lead, 24-7, with little variation. Those with major depression experience the depressive lows almost like waves.
Dysthymia. Is a form of chronic, low grade depression lasting at least 2 yrs in adults ; at least 1 yr in children. A person w dysthymia often feels low ; /or guilty, is self- critical, tired, lacks joy, is disinterested in activities. S/he may have trouble making decisions ; focusing ; struggles with irritability / angry. Self esteem is poor mixed w hopelessness ; problems w sleep ; /or appetite.