Persistent Depressive Disorder

Background

• Persistent depressive disorder (PDD) is defined as a depressed mood for most of the day for a majority of days lasting ≥ 2 years in adults or ≥ 1 year in adolescents and children.
• PDD is a Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) consolidation of dysthymia and chronic major depressive disorder (MDD), and has 4 possible presentations:
  • PDD with pure dysthymic syndrome (formerly dysthymia) - depressive symptoms for ≥ 2 years but criteria for MDD not met
  • PDD with persistent major depressive episode (formerly chronic major depressive disorder) - a persistent form (≥ 2 year duration) of MDD that meets criteria for both PDD (dysthymia) and MDD
  • PDD with intermittent major depressive episode (formerly double depression) - coexistence of both PDD and a concurrent episode of MDD (without chronic MDD)
  • PDD with intermittent major depressive episode without current MDD episode - PDD and history of MDD but MDD criteria are not currently met
• There are also symptomatic, course, and severity specifiers to PDD that may be clinically useful and may help determine treatment.
• The prevalence of PDD worldwide is estimated between 1% and 5% of children, adults, and the elderly.
• Psychosocial factors may increase the risk of PDD, including acute loss (bereavement), substance abuse, childhood mistreatment, domestic abuse, traumatic events (such as car accidents), family history of depressive disorders, racial/ethnic minority status, and low socioeconomic status or financial difficulties.

Evaluation

• The diagnosis is based on clinical history and physical exam findings that meet Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) criteria for persistent depressive disorder (PDD). Ask about somatic complaints such as pain, fatigue, and sleep problems as many patients do not initially complain of depressed mood.
• Several mnemonics are considered helpful for evaluation of symptoms of PDD, such as SIGECAPS (sleep, interest, guilt, energy, cognition, appetite, psychomotor, suicide), C GASP DIE (concentration, guilt, appetite, sleep, psychomotor, death or suicide, interest, energy), or DEPRESSION (depressed mood, energy loss/fatigue, pleasure lost, retardation or excitation, eating changed [appetite/weight], sleep changed, suicidal thoughts, I'm a failure [loss of confidence], only me to blame [guilt], no concentration).
• Ask the patient directly about suicidal ideation and intent and continue to evaluate throughout disease course.
• Use a standardized instrument, such as the Diagnostic Interview Schedule, to aid in diagnosing and assessing severity of depression if suspected based on risk factors or presentation.
• Consider blood tests to assess for other causes of depressive symptoms or conditions associated with depression, including thyroid function tests; kidney and liver function tests; complete blood count; electrolytes, including calcium, vitamin B12 levels, cortisol levels; and HIV testing.

Management

• Hospitalization should be considered for patients who pose serious threat of harm to self or others.
• Develop a treatment plan for patients with persistent depressive disorder (PDD) after assessing the severity of their symptoms.
  • For patients with mild PDD, consider initiation of an antidepressant as the initial treatment.
  • For PDD in patients with a major depressive disorder (MDD) component, offer a combined pharmacotherapy and psychotherapy as the initial therapy.
• Various antidepressants appear to be similarly effective in the treatment of persistent depressive disorder, including selective serotonin reuptake inhibitors (SSRIs), tricyclics (TCAs) or tetracyclic antidepressants (TeCAs).
• Psychotherapy, and particularly cognitive behavioral therapy (CBT), may be associated with depression symptom reduction in patients with persistent depressive disorder.
• Combined pharmacotherapy and psychotherapy should be considered for adults with chronic depression and may increase remission.
• Patients with PDD often need to continue medication indefinitely for maximal treatment effect.
• For patients with continuing chronic depressive symptoms despite pharmacotherapy and/or psychotherapy, consider a change of medication or therapy, establish a follow-up plan, and develop realistic goals to improve functioning and self-management skills.
• Comanagement or referral to a specialty mental health clinician is indicated if the patient is at high risk of suicide, treatment response is inadequate, other psychiatric disorders are present, or if psychosocial needs are complex.