How long must symptoms persist to diagnose Persistent Depressive Disorder (Dysthymia)?

• A. At least 1 year
• B. At least 6 months
• C. At least 3 years
• D. At least 2 years

Answer: (D)

Persistent Depressive Disorder is a chronic form of depression, defined by a depressed mood that lasts for a long continuous period. In adults, the minimum duration is at least two years of depressed mood most of the day, for most days, without a break of more than about two months. That long duration distinguishes this condition from episodic major depression. The other options don’t meet this adult criterion: one year is the pediatric threshold, six months is too short, and three years is longer than the minimum but not the standard requirement. Therefore, at least two years is the correct duration.