For diagnosis of major depression, ≥ 5 of the following must have been present nearly every day during the same 2-week period, and one of them must be depressed mood or loss of interest or pleasure: Depressed mood most of the day Markedly diminished interest or pleasure in all or almost all activities for most of the day Significant (> 5%) weight gain or loss or decreased or increased appetite Insomnia (often sleep-maintenance insomnia) or hypersomnia Psychomotor agitation or retardation observed by others (not self-reported) Fatigue or loss of energy Feelings of worthlessness or excessive or inappropriate guilt Diminished ability to think or concentrate or indecisiveness Recurrent thoughts of death or suicide, a suicide attempt, or a specific plan for committing suicide Persistent depressive disorder Depressive symptoms that persist for ≥ 2 years without remission are classified as persistent depressive disorder (PDD), a category that consolidates disorders formerly termed chronic major depressive disorder and dysthymic disorder.