What is the recommended initial treatment—including psychotherapy and first‑line medication—for a 15‑year‑old 10th‑grade student with depressive symptoms, no confirmed autism diagnosis, who wishes to start therapy and possibly medication?

Initial Treatment for Adolescent Depression

For this 15-year-old with depressive symptoms, start with cognitive behavioral therapy (CBT) or interpersonal psychotherapy as first-line treatment, and if symptoms are moderate-to-severe, add fluoxetine 10-40 mg/day as the only FDA-recommended antidepressant for this age group. 1, 2

Treatment Selection Based on Severity

Mild Depression (5-6 symptoms, mild impairment)

• Active monitoring ("watchful waiting") is appropriate for mild depression without immediate pharmacotherapy 2
• Initiate evidence-based psychotherapy: CBT (effect size 0.5-2.0) or interpersonal psychotherapy (effect size 0.5-0.6) 3
• Schedule follow-up within 1-2 weeks to reassess symptom trajectory 1

Moderate-to-Severe Depression (≥7 symptoms or significant functional impairment)

• Combination therapy with fluoxetine plus CBT is superior to either treatment alone (71% response rate vs. 60.6% for fluoxetine alone vs. 43.2% for CBT alone) 4
• Fluoxetine monotherapy (10-40 mg/day) is statistically superior to CBT monotherapy if psychotherapy access is limited 4
• The combination shows the greatest reduction in suicidal thinking compared to monotherapy 4

First-Line Medication: Fluoxetine Only

Fluoxetine is the only antidepressant with consistent efficacy data and FDA approval for adolescent depression (effect size 0.3-5.6) 3, 5

Second-Line Medication Options (if fluoxetine fails or is not tolerated)

• Escitalopram, citalopram, or sertraline may be considered, though evidence is weaker 3, 5
• Avoid tricyclic antidepressants—they are ineffective in children and adolescents 6

Critical Safety Monitoring

Black Box Warning for Suicidality

• 1-3 per 100 youth taking antidepressants will experience new or worsening suicidal ideation 7
• Weekly monitoring for the first 4 weeks, then biweekly for the next 4 weeks, then monthly 2, 6
• Provide explicit safety planning and educate patient and family about warning signs 6

Monitoring Schedule

• Assess suicidal ideation, medication side effects, and symptom improvement at each visit 2
• Use standardized depression rating scales to track treatment response 1
• If no improvement after 6-8 weeks at therapeutic dose, consider switching medications or adding psychotherapy 2

Special Considerations for This Patient

Autism Spectrum Traits Without Formal Diagnosis

• The patient attends a specialized school but lacks official diagnosis—this does not change the depression treatment algorithm 1, 2
• CBT may require adaptation for communication style and social processing differences, but remains first-line 3
• Monitor for medication side effects carefully, as sensory sensitivities may be present

Psychotherapy as Essential Component

• Even when prescribing medication, concurrent psychotherapy improves outcomes and reduces suicidal thinking 4
• CBT focuses on cognitive restructuring and behavioral activation 3
• Interpersonal psychotherapy addresses relationship conflicts and role transitions 3
• Sessions typically occur weekly for 12-16 weeks 2

Common Pitfalls to Avoid

• Do not prescribe SSRIs other than fluoxetine as first-line—the evidence base is strongest for fluoxetine 3, 5
• Do not use tricyclic antidepressants—they lack efficacy in youth 6
• Do not delay treatment while waiting for specialty mental health referral—primary care management is appropriate and necessary 1, 2
• Do not prescribe antidepressants without establishing close follow-up—the suicide risk requires active monitoring 6, 7

Treatment Algorithm Summary

1. Assess severity using DSM-5 criteria and functional impairment 1
2. Mild depression: Start CBT or interpersonal psychotherapy alone with active monitoring 2, 3
3. Moderate-to-severe depression: Initiate fluoxetine 10-40 mg/day PLUS CBT 4
4. Monitor weekly × 4 weeks for suicidality and side effects 2, 6
5. Reassess at 6-8 weeks: If inadequate response, increase dose, switch medications, or intensify psychotherapy 2
6. Continue treatment for 6-12 months after symptom remission to prevent relapse 2