Persistent Depressive Disorder
Persistent depressive disorder (dysthymia) is a chronic, lower-grade depression lasting 2 years or longer, defined per DSM-5.
Symptoms
A depressed mood most of the day, more days than not, for at least 2 years, along with at least two of: poor appetite or overeating, sleep disturbance, low energy, low self-esteem, poor concentration, or hopelessness.
Causes and risk
Similar to major depression -- genetics, brain chemistry, and chronic stress -- but the lower-grade, longer-lasting course means it can go unrecognized for years, sometimes described as someone's "baseline" personality rather than an illness.
How it is evaluated
Diagnosis follows DSM-5 duration and symptom criteria; ruling out medical causes such as hypothyroidism and substance use is an essential step, and "double depression" (a major depressive episode layered on dysthymia) is a recognized pattern, per clinical review data.
Treatment
Psychotherapy (including CBASP, a therapy developed specifically for chronic depression) and antidepressants are both used, often in combination, per the American Psychological Association guideline; up to half of patients do not respond fully to an initial treatment trial, so a change in approach is common and expected.
When to seek care
Any thoughts of suicide or self-harm require immediate crisis support -- call 911 or the 988 Suicide and Crisis Lifeline. A new depressive episode layered on chronic symptoms should also prompt a check-in with your care team.