Described as a depressive disorder, persistent depressive disorder is a more chronic form of depression: its diagnosis can be made when the mood disorder continues for at least 2 years in adults, or 1 year in children.
This diagnosis – a new entry in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) – includes chronic major depression and dysthymia, previously described in DSM-IV.
Approximately 6% of adults are affected, and women are affected about twice as much as men. Although it can start at any age, late onset is uncommon; the gradual and early onset leads some patients to consider their usually low mood as normal.
Signs and symptoms of persistent depressive disorder
Persistent depressive disorder is characterized by the presence of depressed mood for the most part of the day for at least 2 years
Persistent depressive disorder is characterized by the presence of depressed mood for most of the day for at least 2 years (1 in children and adolescents), associated with poor or excessive appetite, insomnia or hypersomnia, fatigue, low self-esteem, lack of concentration, feelings of hopelessness.
It differs from major depressive episode for the longer duration and the absence of unjustified feelings of guilt, thoughts of death or suicidal ideas. Therefore, people with this disorder suffer from a long-lasting, but also relatively mild disease.
Affected patients suffer silently, and their disability can be subtle: they tend to put a lot of energy into work, leaving little to the social aspects of life. Since they do not appear severely disabled, they can go on without treatment until symptoms worsen into a major depressive episode. The DSM-IV differentiated dysthymic disorder from chronic major depressive disorder, however research has not confirmed such distinction. Therefore, what the DSM-V now calls persistent depressive disorder is a combination of the two conditions considered separately in the DSM-IV.
These symptoms are often described as “low-grade depression”, and occur most often for 2 years (they are never absent for more than 2 consecutive months).
Some patients are not even aware that they are depressed, although others may notice it. They recognize symptoms such as fatigue, trouble concentrating or making decisions, low self-esteem and feelings of hopelessness. Sleep and appetite can be increased or decreased.
Persistent depressive disorder often has an early and insidious onset (for example, in childhood, adolescence, or adulthood) and – by definition – a chronic course.
An early onset (i.e. before age 21) is frequently associated with the presence of personality and substance use disorders.
Risk factors for persistent depressive disorder
Risk factors are a family history of mood disorders and the loss or separation of parents during childhood.
Some factors have been observed to negatively affect the course of the disease: higher levels of neurosis (negative affectivity: tendency to a gloom and doom attitude, pessimism), greater severity of symptoms, poorer overall functioning (for example, the person fails to be brilliant, to perform well in the social and work context) and presence of anxiety or conduct disorder.
The brain circuit involving the prefrontal cortex, anterior cingulate cortex, amygdala and hippocampus has been observed to be involved in the development of persistent depressive disorder.
Treatment of persistent depressive disorder
Studies conducted on dysthymia showed that antidepressant therapy was effective in treating the disorder compared to placebo and showed a greater efficacy than the psychotherapeutic intervention alone.
However, it’s the combination therapy consisting of antidepressants and psychotherapy to show the best results.
Psychotherapy aims at a greater self-awareness, at reducing self-destructive behaviors (such as negativity, despair and lack of assertiveness), at improving the ability to function in interpersonal social and work situations and at teaching problem-solving strategies
- Diagnostic and Statistic Manual of Mental Disorders, fifth edition, American Psychiatric Association
- Williams JW., Barrett J., Oxman T., Frank E., Katon W., Sullivan M., Cornell J., Sengupta A. Treatment of Dysthymia and Minor Depression in Primary Care: A Randomized Controlled Trial in Older Adults. Jama, 2000 Sep 27;284(12):1519-26.