Persistent depressive disorder, also known as dysthymia, is a milder form of depression, but the patient is rarely without symptoms.  Symptoms of dysthymia include poor appetite or overeating, insomnia or hypersomnia, low energy or fatigue, low self-esteem, poor concentration or difficulty making decisions, and feelings of hopelessness.  Two or more of these symptoms must be present for the diagnosis of persistent depressive disorders and these symptoms cannot be absent for more than two months during a two year period.  Dysthymia has a lifetime risk of about three percent for the average person in a sample of more than nine thousand people in interviews by the National Comorbidity Survey Replication.

The typical onset for a depressive mood disorder is age thirty-two, but this may vary.  Lengths in depressive episodes vary, but must last at least two weeks and usually have to have at least two episodes.  Episodes may reoccur and may be divided with periods of partial or full recovery.  Half of all depressive patients recover within six months of an episode, and after a full recovery are less likely to relapse as the remission period gets longer.

Risk factors may include stressful life events, how people react to events in society surrounding them, genetic predisposition, hormone imbalances of the endocrine glands, brain structure, and neurotransmitter misfires.

Treatments may include interpersonal therapy focusing on relationships especially with family and antidepressant medication