ICD-10 F42: OCD Diagnosis Codes and Therapy Billing Guide

ICD-10 F42 codes cover Obsessive-Compulsive Disorder and related presentations. OCD billing requires understanding the F42 subcode cluster, how hoarding disorder is coded separately, and why Exposure and Response Prevention (ERP) treatment documentation supports medical necessity for longer sessions.

What Does ICD-10 F42 Mean?

F42 maps to the DSM-5 chapter on Obsessive-Compulsive and Related Disorders. The core clinical requirement for any F42 code is the presence of obsessions (recurrent, intrusive thoughts, urges, or images causing distress) and/or compulsions (repetitive behaviors or mental acts performed in response to obsessions) that are time-consuming (over 1 hour/day) or cause clinically significant distress or impairment.

F42 Subcodes

OCD vs Hoarding: Separate Billing Since DSM-5

Prior to DSM-5, hoarding was considered a symptom of OCD. DSM-5 elevated it to a standalone diagnosis. For billing purposes:

• Client with classic OCD (obsessions + compulsions, no significant hoarding) → F42.2
• Client with hoarding as the primary presentation → F42.3
• Client with both OCD and significant hoarding → bill both F42.2 and F42.3 on the superbill, with the primary treatment focus listed first
• Hoarding disorder often requires specialized CBT protocols distinct from standard ERP — document the specific treatment approach

ERP Treatment and Billing Documentation

Exposure and Response Prevention (ERP) is the evidence-based treatment for OCD. ERP sessions are often longer and more complex than standard supportive therapy. Billing implications:

• ERP sessions frequently warrant 90837 (60-minute sessions) because in-session exposure exercises require time to complete the full anxiety response cycle
• Document the specific exposure hierarchy, the target obsession/compulsion, and the session's outcome in your notes to support 90837 over 90834
• Some payers may request a treatment plan update after 20 sessions for OCD — plan for periodic medical necessity documentation

CPT Codes Commonly Paired With F42

• 90837 — 60-minute individual psychotherapy. The standard for active ERP treatment.
• 90834 — 45-minute individual psychotherapy. Appropriate for psychoeducation sessions, maintenance phase, or structured CBT protocols that fit in 45 minutes.
• 90791 — Psychiatric diagnostic evaluation. Use at intake; document Yale-Brown OCS (Y-BOCS) score or equivalent severity measure to establish baseline.
• 90847 — Family therapy with client present. Particularly relevant for pediatric OCD where family accommodation is a treatment target; document the accommodation patterns addressed in the session.

Documentation Requirements

• Obsession content and compulsion type documented explicitly
• Time estimate: obsessions/compulsions consume more than 1 hour per day, or cause significant distress/impairment
• Y-BOCS score (or equivalent) at intake and periodically during treatment
• ERP treatment plan with exposure hierarchy
• For F42.3 (hoarding): clutter image rating, difficulty discarding documented, level of functional impairment (room use, fire hazard, relationship impact)
• Rule-out of body dysmorphic disorder, PTSD, and major depression as primary diagnoses if obsessive themes are mood-congruent

Common Denial Reasons

• OCD confused with anxiety: Some clinicians default to F41.1 or F41.9 for intrusive thoughts. If the presentation meets OCD criteria, use F42.2 — it is more specific and better supports ERP as a treatment modality.
• 90837 billed without ERP documentation:Longer sessions for OCD treatment need to be justified by notes that describe the ERP work performed, not just “supportive therapy.”
• Prior authorization gaps: A small number of payers require PA for OCD treatment beyond an initial evaluation. Verify benefits before the first session.

Generate a Superbill With F42

Superbilled supports all F42 subcodes and generates a complete superbill with the correct diagnosis, CPT code, and provider fields. Create your superbill now.