Persistent depressive disorder

Persistent depressive disorder (PDD) includes common forms of depression, but lasting longer than acute major depressive disorder.

Frequently misdiagnosed because the correct criteria to diagnose this condition are often not applied. Affected patients have a depressed mood most of the day, for more days than not, for at least 2 years. While depressed, patients have at least 2 of: poor appetite/overeating, insomnia or hypersomnia, low energy/fatigue, low self-esteem, poor concentration or difficulty making decisions, or feelings of hopelessness. Symptoms do not remit for more than 2 months at a time.

Associated with significant functional impairment (including unemployment, difficulty establishing intimate relationships, greater healthcare utilization, greater utilization of public entitlements).

Patients may respond to pharmacotherapy, psychotherapy, or a combination of both.

Patients require a longer treatment period, more psychotherapy sessions, and/or higher doses of antidepressants compared with patients with acute forms of depression.

Like other mood disorders, PDD is frequently comorbid with other psychiatric and medical conditions.

PDD is a category that includes various forms of chronic depression in which depressive symptoms are present "more days than not" over at least a 2-year period (1 year in children and adolescents).[1]American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 5th ed., text revision (DSM-5-TR). Washington, DC: American Psychiatric Publishing; 2022.

Subtypes of PDD include:

1) Pure dysthymia without full criteria for major depression during the preceding 2 years

2) Persistent major depressive episode (full criteria for a major depressive episode have been met during the preceding 2 years)

3) Intermittent major depressive episodes with current episode (full criteria for a major depressive episode are currently met, but there have been periods of at least 8 weeks in at least the preceding 2 years with symptoms below the threshold for a full major depressive episode)

4) Intermittent major depressive episodes without current episode (full criteria for a major depressive episode are not currently met, but there has been one or more major depressive episodes in at least the preceding 2 years)

PDD may have early onset (before age 21 years) or late onset (at age 21 years or older). In addition, there may be the presence of "anxious distress", which includes feelings of being keyed up or on edge, restlessness, difficulty concentrating because of worry, feelings that something awful may happen, and fears of loss of control.

PDD may have "atypical features", which include mood reactivity; weight gain; increased sleep; heavy, leaden feelings in limbs; and sensitivity to interpersonal rejection that results in significant social or occupational impairment.

NOTE: It is important to specify that the term "persistent depressive disorder" includes the 4 different categories noted above. Prior research, including outcome studies, epidemiologic studies, and meta-analyses and other reviews, has generally followed DSM-IV categories, not the consolidated DSM-5-TR category. Hence, previous studies of "dysthymia" generally include patients presenting in subtypes 1) (pure dysthymia) and 4) (current dysthymia, prior major depressive disorder [MDD]), with a small number of studies of pure dysthymia (category 1 alone). Other studies have been conducted for category 2) (chronic major depression). Those patients presenting with category 3) (dysthymia with current MDD, or so-called "double depression") are generally included in studies of major depressive disorder, and comorbid dysthymia may or may not be specified. In general, in studies cited in this topic, if they refer to "dysthymic disorder" the subtypes 1 and 4 are included; if they refer to “chronic major depression”, they include subtype 2. Also of note, studies of "major depression" often include patients with coexisting dysthymia, and may or may not specify the percentage of patients with chronicity.

In contrast to the DSM-5-TR, which combined the diagnosis of dysthymic disorder with other forms of chronic depression into the category of persistent depressive disorder, the ICD-11 has retained a separate classification of dysthymic disorder.[2]First MB, Gaebel W, Maj M, et al. An organization- and category-level comparison of diagnostic requirements for mental disorders in ICD-11 and DSM-5. World Psychiatry. 2021 Feb;20(1):34-51. https://onlinelibrary.wiley.com/doi/10.1002/wps.20825 http://www.ncbi.nlm.nih.gov/pubmed/33432742?tool=bestpractice.com