What is the recommended approach for a general practitioner to diagnose and treat depression?

Diagnosis and Treatment of Depression in Primary Care

As a GP, you should systematically screen patients using validated tools (PHQ-9 or two-question screen), diagnose based on DSM-5 criteria, and initiate treatment with either cognitive behavioral therapy (CBT) or a second-generation antidepressant (SSRI/SNRI) as monotherapy for moderate-to-severe depression, with close monitoring starting within 1-2 weeks. 1, 2, 3

Screening and Case-Finding

Use structured screening approaches:

• Ask two simple questions: "Over the past 2 weeks, have you felt down, depressed, or hopeless?" and "Over the past 2 weeks, have you felt little interest or pleasure in doing things?" 4
• Alternatively, use PHQ-9 or other validated instruments
• Target high-risk patients including those with: previous depression history, family history of mood disorders, chronic medical conditions, substance use, recent trauma, frequent somatic complaints, or psychosocial adversity 5

Critical caveat: A positive screen does NOT equal a diagnosis—it triggers comprehensive assessment 5

Diagnostic Assessment

Confirm diagnosis using DSM-5 criteria requiring:

• Depressed mood OR anhedonia (loss of interest/pleasure) for ≥2 weeks
• Plus ≥5 total symptoms: sleep disturbance, appetite/weight change, psychomotor changes, fatigue, worthlessness/guilt, concentration problems, or suicidal thoughts 1

Essential assessment components:

• Rule out medical causes first: Check for uncontrolled pain, thyroid dysfunction, anemia, electrolyte imbalances, medication side effects 6
• Assess suicide risk immediately: Any patient at risk of self-harm requires emergency psychiatric evaluation 6
• Screen for comorbidities: 50-60% have comorbid anxiety disorders; also assess for substance use and other psychiatric conditions 6
• Evaluate functional impairment in work, relationships, and daily activities 6, 5

Treatment Algorithm by Severity

Mild Depression

Start with low-intensity interventions: 7

• Active monitoring with scheduled follow-up
• Psychoeducation about depression
• Behavioral activation and sleep hygiene
• Physical activity/exercise programs
• Do NOT use antidepressants as first-line 7
• Consider CBT monotherapy if resources available 2, 3

Moderate-to-Severe Depression

Choose ONE of three evidence-based options: 2, 3

1. CBT monotherapy (8-16 sessions)
2. Second-generation antidepressant monotherapy
3. Combination therapy (CBT + antidepressant)

Selecting antidepressants—no single agent is superior in efficacy: 1

• First-line: SSRIs (fluoxetine, sertraline, citalopram, escitalopram) or SNRIs (venlafaxine, duloxetine)
• Base choice on: adverse effect profile, drug interactions, prior response, cost, and patient preference 6, 1
• Key differences in side effects:
  • Bupropion: lower sexual dysfunction rates 1
  • Paroxetine: higher sexual dysfunction 1
  • SSRIs: increased GI bleeding risk (especially with NSAIDs/aspirin), suicidal ideation in ages 18-29 4

Dosing: Start at therapeutic doses per standard guidelines; underdosing is a common pitfall 1

Monitoring and Follow-Up

Structured reassessment schedule: 1

• Week 1-2: Initial contact to assess tolerability, side effects, and suicide risk (FDA black box warning period) 1
• Weeks 2-8: Biweekly or monthly visits to monitor response, adherence, and adverse effects 6
• Use outcome measures: Repeat PHQ-9 or similar tools to quantify improvement 6

Common pitfall: Patients with depression often lack motivation for follow-up—proactively schedule appointments and address barriers to adherence 6

Treatment Modification for Non-Response

If inadequate response after 6-8 weeks of adequate treatment: 1, 3

Choose one strategy:

1. Switch to different second-generation antidepressant (different class preferred)
2. Augment with CBT (if started with medication alone)
3. Augment with second pharmacologic agent: atypical antipsychotic or lithium (specialist consultation recommended)
4. Switch to CBT (if started with medication alone)

The evidence does NOT strongly favor one strategy over another—personalize based on patient factors 3

Duration of Treatment

Continuation phase (after symptom remission): 1

• First episode: Continue treatment 4-9 months minimum
• Two or more episodes: Consider indefinite maintenance therapy
• Stopping prematurely is a major cause of relapse

Special Considerations

Comorbid anxiety: Treat depression first; many antidepressants effectively treat both conditions 6

Patient education is mandatory: 6

• Explain expected timeline for improvement (2-4 weeks)
• Warn about potential side effects
• Specify warning signs requiring immediate contact (worsening suicidal thoughts, agitation, unusual behavior changes)
• Discuss that depression is treatable and not a personal weakness

Stepped care model: Tailor intensity of intervention to symptom severity, functional impairment, risk factors, treatment history, and patient preference 6

Key Pitfalls to Avoid

• Diagnosing depression based on screening alone without clinical assessment
• Starting antidepressants for mild depression without trying psychotherapy/behavioral interventions first
• Inadequate monitoring in first 2 weeks (suicide risk period)
• Changing treatment before 6-8 week adequate trial
• Stopping treatment too early after remission
• Ignoring medical causes of depressive symptoms
• Failing to assess and document suicide risk at every visit