What are the diagnostic criteria and treatment options for major depressive disorder?

Diagnostic Criteria and Treatment Options for Major Depressive Disorder

Major depressive disorder (MDD) is diagnosed when a patient exhibits depressed mood or loss of pleasure/interest along with at least four additional symptoms lasting at least 2 weeks, with treatment options including cognitive behavioral therapy or second-generation antidepressants as equally effective first-line treatments.

Diagnostic Criteria for MDD

• MDD is defined by the American Psychiatric Association as depressed mood or loss of pleasure/interest along with other symptoms that last for at least 2 weeks and affect normal functioning 1

• Diagnosis requires at least 5 of the following symptoms during a 2-week period, with at least one being depressed mood or anhedonia 2:

  • Depressed mood most of the day, nearly every day
  • Markedly diminished interest or pleasure in almost all activities
  • Significant weight loss/gain or decreased/increased appetite
  • Insomnia or hypersomnia
  • Psychomotor agitation or retardation
  • Fatigue or loss of energy
  • Feelings of worthlessness or excessive/inappropriate guilt
  • Diminished ability to think or concentrate, or indecisiveness
  • Recurrent thoughts of death or suicide 1, 2

• Diagnosis can be made through standard clinical evaluation based on DSM-5 criteria or through structured clinical assessments such as the Mini International Neuropsychiatric Interview or Structured Clinical Interview 1

Assessment Tools

• The Patient Health Questionnaire-9 (PHQ-9) and Hamilton Depression Rating Scale (HAM-D) are commonly used to assess depression severity and monitor treatment response 1, 2
• The Montgomery-Åsberg Depression Rating Scale (MADRS) is recommended with moderate consensus as the preferred clinician-administered outcome instrument, along with the patient-reported Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) 1
• Response to treatment is typically defined as ≥50% reduction in measured severity using these validated tools 1

First-Line Treatment Options

• The American College of Physicians strongly recommends either cognitive behavioral therapy (CBT) or second-generation antidepressants (SGAs) as first-line treatment for MDD after discussing benefits, risks, costs, accessibility, and patient preferences 1
• This recommendation is based on moderate-quality evidence showing similar effectiveness between these approaches 1

Pharmacotherapy Options

• Second-generation antidepressants, particularly SSRIs or SNRIs, are recommended first-line pharmacological treatments 3

• Initial dosing recommendations:

  • Fluoxetine: Start with 20 mg/day in the morning for adults 4
  • Sertraline: Start with 50 mg once daily for adults 5
  • Bupropion XL: Start with 150 mg once daily in the morning, may increase to 300 mg after 4 days 6

• Treatment should be continued for at least 4-9 months after satisfactory response for first episodes, with longer duration beneficial for recurrent episodes 3, 5

Psychotherapy Options

• Cognitive Behavioral Therapy (CBT) has moderate-quality evidence supporting its effectiveness as equivalent to SGAs 1, 3
• Other evidence-based psychotherapies include interpersonal therapy, acceptance and commitment therapy, and psychodynamic therapies 1, 7

Treatment Phases

• Depression treatment follows three distinct phases 1:
  • Acute phase (6-12 weeks): Goal is symptom reduction
  • Continuation phase (4-9 months): Prevents relapse
  • Maintenance phase (≥1 year): Prevents recurrence, especially important for patients with multiple episodes 1, 3

Treatment-Resistant Depression

• Treatment-resistant depression (TRD) is commonly defined as failure to respond to two or more adequate antidepressant trials 1
• An adequate trial requires sufficient dose and duration (typically minimum 4 weeks) 1
• For TRD, options include medication switch, augmentation strategies, combination therapy, or somatic therapies like electroconvulsive therapy 7

Common Pitfalls to Avoid

• Inadequate dosing or premature discontinuation before therapeutic effects are achieved (typically 4-6 weeks) 3
• Failure to monitor for suicidality, especially during initial treatment period 3, 6
• Not recognizing that vegetative symptoms (sleep, energy, appetite) are often more central to clinical depression than feelings of worthlessness or guilt 8
• Overlooking residual symptoms like fatigue, sleep disturbance, anxiety, and cognitive dysfunction, which may persist despite improvement in mood 9
• Not continuing treatment long enough to prevent relapse (minimum 4-9 months after response) 3, 5