Mental Health

Persistent depressive disorder (PDD)

Chronic depressive mood disorder characterized persistent but mild depression for more than 2 years.


Chronic depressive mood disorder characterized persistent but mild depression for more than 2 years.


In the past, this disease was considered a depressed personality state, but it is likely better conceptualized as a disease state rather than a personality disorder (permanent, pervasive way of approaching the world). This change is reflected in the history of the diagnosis as the DSM-II originally identified it as a personality disorder. It was not until the DSM-III that dysthymic disorder was defined as a mild chronic depression lasting longer than 2 years. The origin of the word dysthymia dates back to its Greek roots with the first use of the word referring to psychiatry occurring by CF Fleming around 1844.

DSM-5 has consolidated chronic major depression and dysthymia from DSM-IV into persistent depressive disorder; this means that a patient may meet the criteria for persistent depressive disorder and major depressive disorder at the same time.

Clinical features

Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria:

Patient must have a depressed mood for at least 2 years.  For children or adolescents, the mood can be irritable instead of depressed and the time requirement is 1 year.  For both groups, symptoms cannot be absent for greater than 2 months. In addition to depressed/irritable mood at least 2 of the following symptoms have to be present.  
  1. Poor appetite or overeating
  2. Insomnia or hypersomnia
  3. Low energy/fatigue
  4. Low self-esteem
  5. Poor concentration/decision making
  6. Hopelessness

Clinical signs:

  • Omega sign “omega melancholicum”: Peculiar furrowing of glabellar skin above the dorsum of the nose resembling the greek alphabet ‘Ω’
  • Veraguth’s fold: Triangular palpebral folds running diagonally from the lateral corners of the eyes, medially upward to the medial end of the eyebrows
Vertical wrinkling between the eyebrows joined at the top by a horizontal crease (Omega sign sign-white arrow); also shows diagonal palpebral folds running medially upward (Veraguth’s sign-black arrow) | Saraf, A. S., & Nath, S. (2019). Revisiting Omega and Veraguth’s Sign. Indian journal of psychological medicine, 41(3), 295–297.


Treatment and management of persistent depressive disorder do not vary significantly from the treatment and management of a major depressive disorder.


  • Selective serotonin reuptake inhibitors (SSRIs): First-line for late-onset depression
    • Citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, vilazodone, vortioxetine
  • Serotonin/norepinephrine reuptake inhibitors (SNRIs): In patients non-responsive to SSRIs and first-line agents in cases with significant fatigue/pain syndromes associated with depression
    • Venlafaxine, desvenlafaxine, duloxetine, and levomilnacipran
  • Atypical antidepressants: Bupropion, mirtazapine, nefazodone, and trazodone
  • Serotonin-Dopamine Activity Modulators (SDAMs): Partial agonist at 5-HT1A and dopamine D2 receptors at similar potency, and as an antagonist at 5-HT2A and noradrenaline
    • Brexpiprazole and aripiprazole
  • Tricyclic antidepressants (TCAs): Amitriptyline, clomipramine, desipramine, doxepin, imipramine, nortriptyline, protriptyline, trimipramine
  • Monoamine oxidase inhibitors (MAOIs): Isocarboxazid, phenelzine, selegiline, and tranylcypromine


  • Cognitive behavior therapy (CBT): Structured, and didactic form of therapy that focuses on helping individuals identify and modify maladaptive thinking and behavior patterns (16-20 sessions).
  • Interpersonal therapy: Time-limited (typically 16 sessions) treatment for major depressive disorder which draws from attachment theory and emphasize the role of interpersonal relationships, focusing on current interpersonal difficulties.

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