chronic depression

The depression symptoms can linger for a long period of time, often two years or longer. Those who suffer from dysthymia can also experience periods of major depression--sometimes called "double depression.".

The symptoms of dysthymia are the same as those of major depression but fewer in number and not as intense. They include the following:

    -Sadness or depressed mood most of the day or almost every day
    Loss of enjoyment in things that were once pleasurable
    Major change in weight (gain or loss of more than 5% of weight within a month) or appetite
    Insomnia or excessive sleep almost every day
    Being physically restless or rundown in a way that is noticeable by others
    Fatigue or loss of energy almost every day
    Feelings of hopelessness or worthlessness or excessive guilt almost every day
    Problems with concentration or making decisions almost every day
    Recurring thoughts of death or suicide, suicide plan, or suicide attempt

    As dysthymia is a chronic disorder, sufferers may experience symptoms for many years before it is diagnosed, if diagnosis occurs at all. As a result, they may believe that depression is a part of their character, so they may not even discuss their symptoms with doctors, family members, or friends

    reference.
    http://www.webmd.com/depression/guide/chronic-depression-dysthymia