What is the recommended comprehensive evaluation for a patient with suspected major depressive disorder?

Evaluation of Major Depressive Disorder

Initial Screening and Diagnosis

Use the Patient Health Questionnaire-9 (PHQ-9) as your primary screening and diagnostic tool, as it has excellent sensitivity (80-90%) and is validated for both diagnosis and monitoring treatment response. 1, 2, 3

Screening Implementation

• Administer the PHQ-9 at the initial visit, which takes less than 5 minutes and is based on the 9 DSM-5 depression criteria 4, 1
• A PHQ-9 score ≥10 indicates moderate to severe depression requiring treatment 1, 2
• The 2-item version can serve as a brief screener, but scores ≥3 require completion of the full 9-item version for diagnosis 4
• Critical pitfall: Approximately 60-76% of positive screens are false positives, so you must conduct further diagnostic questioning to confirm the diagnosis before initiating treatment 2

Diagnostic Confirmation

Confirm that the patient meets DSM-5 criteria: at least 5 symptoms present for ≥2 weeks, including either depressed mood or anhedonia, plus additional symptoms (sleep changes, appetite changes, psychomotor changes, fatigue, guilt/worthlessness, concentration problems, or suicidal ideation) 2, 3

Mandatory Risk Assessment

Evaluate suicidal risk at every consultation by asking directly about thoughts of death or suicidal ideation—this is non-negotiable. 1

• Immediate psychiatric referral is required for significant suicidal risk, psychotic symptoms, suspected bipolar disorder, or severe depression with marked functional impairment 1

Functional Impairment Assessment

Assess the impact on work performance, family relationships, social activities, and self-care capacity 1

Additional Assessment Tools for Comprehensive Evaluation

While the PHQ-9 is your primary tool, consider supplementing with:

• Montgomery-Åsberg Depression Rating Scale (MADRS) for clinical trials or research settings, as it has superior sensitivity to treatment changes and focuses on core depressive symptoms 4, 2
• Hamilton Depression Rating Scale (HAM-D) as an alternative clinician-administered scale, though it has lower sensitivity than MADRS 4, 2
• Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) as a patient-reported measure to complement clinician assessment 4, 2

The combination of clinician-administered and self-reported scales is important, as mismatch between scores indicates poor prognosis 4

Special Population Considerations

Patients with Diabetes

• Screen annually for depression using age-appropriate validated measures, as one in four diabetic patients has elevated depressive symptoms 4, 2
• Reassess at diagnosis of diabetic complications or significant medical status changes 4, 2
• Screen for anxiety symptoms related to diabetes complications, medication adherence, and hypoglycemia fears 4, 5

Patients with Stroke

• Screen for poststroke depression, which affects 25-79% of stroke survivors and is associated with higher mortality and poorer functional recovery 4
• The PHQ-9 performs equally well regardless of age, gender, or ethnicity in stroke populations 4

Laboratory and Medical Evaluation

Consider laboratory tests to assess for significant comorbidities, differential diagnoses, or contraindications to treatment 3

Screening Intervals

• For patients with prior depression history, conduct ongoing monitoring within routine care to detect recurrence 2
• Recurrent screening is most productive in patients with depression history, unexplained somatic symptoms, comorbid anxiety or panic disorder, substance abuse, or chronic pain 2

Documentation of Severity

Document depression severity using PHQ-9 scores:

• Scores 5-9: Mild depression
• Scores 10-14: Moderate depression
• Scores 15-19: Moderately severe depression
• Scores ≥20: Severe depression 1, 6

This severity stratification guides treatment intensity and monitoring frequency 1, 6