SMLEREVISE

Major Depressive Disorder: Diagnosis and Treatment

Medically Reviewed by Dr. M. Salar Raza | Official SCFHS 2026 Blueprint

Clinical Pathway

Major Depressive Disorder (MDD) is diagnosed when a patient experiences at least 5 of 9 typical symptoms (including depressed mood or anhedonia) for at least 2 weeks, causing significant impairment. First-line pharmacological treatment for MDD typically involves Selective Serotonin Reuptake Inhibitors (SSRIs) such as sertraline, fluoxetine, or citalopram. Cognitive Behavioral Therapy (CBT) is also a highly effective first-line psychotherapy. A combination of pharmacotherapy and psychotherapy often yields the best outcomes.

Clinical Reasoning

SSRIs are preferred as first-line agents due to their favorable side-effect profile, safety in overdose, and broad efficacy compared to older classes of antidepressants like Tricyclic Antidepressants (TCAs) or Monoamine Oxidase Inhibitors (MAOIs). It is critical to educate patients that antidepressants typically take 4-6 weeks to reach full therapeutic effect, although some improvements in sleep or appetite may be seen earlier. Patients should be closely monitored for worsening depression or emergence of suicidal ideation, particularly upon initiating therapy.

Sample MCQ

A 22-year-old college student presents to the student health center reporting a 4-week history of persistently sad mood, loss of interest in her classes and hobbies, difficulty concentrating, fatigue, and sleeping excessively. She denies any history of manic or hypomanic episodes. Which of the following is the most appropriate first-line medication class for this patient?

  • ATricyclic Antidepressants (TCAs)
  • BSelective Serotonin Reuptake Inhibitors (SSRIs)
  • CBenzodiazepines
  • DMonoamine Oxidase Inhibitors (MAOIs)

Correct Answer: Selective Serotonin Reuptake Inhibitors (SSRIs)

The patient's symptoms (sad mood, anhedonia, poor concentration, fatigue, hypersomnia) lasting for more than 2 weeks are indicative of Major Depressive Disorder (MDD). The first-line pharmacological treatment for MDD is a Selective Serotonin Reuptake Inhibitor (SSRI). SSRIs are preferred over TCAs and MAOIs due to their better tolerability and safety profile. Benzodiazepines are used for anxiety and do not treat the underlying depression.

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