Background
In the American Psychiatric Association’s Diagnostic and Statistical Manual, Fifth Edition (DSM-5), persistent depressive disorder (dysthymia) represents a consolidation of DSM-IV-defined chronic major depressive disorder and dysthymic disorder.
Persistent depressive disorder is a depressive mood disorder characterized by a chronic course and an early and inisidious onset (i.e., in childhood, adolescence, or early adulthood). Early onset (i.e., before age 21) is associated with higher risk for comorbid personality disorders and substance use disorders.
Although dysthymia was traditionally considered less severe than major depression, the consequences of dysthymia are increasingly recognized as grave; they include severe functional impairment, increased morbidity from physical disease, and increased risk of suicide. (See Prognosis.)
Anxious versus anergic dysthymia
Niculescu and Akisal proposed that dysthymia be divided into 2 subtypes: anxious dysthymia and anergic dysthymia. They described the subset of patients with anxious dysthymia as having pronounced symptoms of low self-esteem, undirected restlessness, and interpersonal rejection sensitivity. They also characterized these patients as help-seeking and more likely to make lower-lethality suicide attempts and to have a better response to selective serotonin reuptake inhibitors (SSRIs). Substances of choice for these patients include benzodiazepines, alcohol, marijuana, opiates, and possibly food. (See Treatment and Medication.)
This group is compared with persons who have anergic dysthymia, characterized by low energy, hypersomnia, and anhedonia. Patients with anergic dysthymia, the authors suggest, may have a better response to treatment with agents that increase norepinephrine or dopamine. (See Treatment and Medication.)
Of note, an estimated 75% of people with dysthymia meet criteria for at least 1 major depressive episode, referred to as double depression.
Those with dysthymia who have depressive episodes tend to have longer periods of depression and spend less time fully recovered.
In a 10-year follow-up study of people with dysthymia, 75% experienced some (at least 2 mo) period of recovery from major depression; the mean time to recovery was 52 months from study entry. In this study, most (70%) of those who recovered experienced a relapse into another episode of depression, most commonly in the 3 years following recovery.
Diagnostic criteria (DSM-5)
The specific DSM-5 criteria for persistent depressive disorder (dysthymia) are as follows:
Depressed mood for most of the day, for more days than not, as indicated by either subjective account or observation by others, for at least 2 years. In children and adolescents, mood may be irritable and duration must be at least 1 year.
Presence, while depressed, of two (or more) of the following:
Poor appetite or overeating
Insomnia or hypersomnia
Low energy or fatigue
Low self-esteem
Poor concentration and/or difficulty making decisions
Feelings of hopelessness
During the 2-year period (1 year for children and adolescents) of the disturbance, the individual has never been without symptoms in Criteria A and B for more than 2 months at a time.
Criteria for major depressive disorder may be continuously present for 2 years.
There has never been a manic episode or a hypomanic episode, and criteria have never been met for cyclothymic disorder.
The disturbance is not better explained by a persistent schizoaffective disorder, schizophrenia, delusional disorder, or other specified or unspecified schizophrenia spectrum and other psychotic disorders.
The symptoms are not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition (e.g., hypothyroidism).
The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
As with other depressive disorders, persistent depressive disorder (dysthymia) can be given further specifiers:
With anxious distress
With mixed features
With melancholic features
With atypical features
With mood-congruent psychotic features
With mood-incongruent psychotic features
With peripartum onset