OCD ICD-10 codes: F42.2, F42.3, F42.4, F42.8 and F42.9

In this article▾

1. What is the ICD-10 code for OCD?
2. F42.2: Mixed obsessional thoughts and acts
3. F42.3: Hoarding disorder
4. F42.4: Excoriation (skin-picking) disorder
5. F42.8: Other obsessive-compulsive disorder
6. F42.9: Obsessive-compulsive disorder, unspecified
7. How to choose between F42.2, F42.3, F42.8, and F42.9
8. OCD documentation and medical necessity
9. Assessment instruments and clinical documentation
10. Common OCD ICD-10 coding mistakes
11. Frequently asked questions
12. Sources and coding references

The ICD-10-CM category for obsessive-compulsive disorder (OCD) is F42. However, F42 is a nonbillable category header. Clinicians and billing teams must select the appropriate billable code based on the documented diagnosis.

The most relevant codes include F42.2 for mixed obsessional thoughts and acts, F42.3 for hoarding disorder, F42.4 for excoriation (skin-picking) disorder, F42.8 for other obsessive-compulsive disorder, and F42.9 for obsessive-compulsive disorder, unspecified.

The distinction matters because these codes do not all describe the same diagnosis. Hoarding disorder and excoriation disorder are separate obsessive-compulsive and related disorders, not simply different presentations of OCD.

For clinicians, accurate coding starts with the diagnosis established in the assessment, followed by documentation that supports the selected code and the services being delivered.

What is the ICD-10 code for OCD?

F42 is the ICD-10-CM category for obsessive-compulsive disorder. It is not itself a billable code. The appropriate child code should be selected based on the clinical diagnosis and the current ICD-10-CM Tabular List.

These are U.S. ICD-10-CM codes, and the numbering has a gap worth understanding. The international WHO ICD-10 has F42.0, predominantly obsessional thoughts or ruminations, and F42.1, predominantly compulsive acts. Neither exists in ICD-10-CM. There is no U.S. code for obsessions-only or compulsions-only OCD; F42.2, mixed obsessional thoughts and acts, is the only presentation-specific OCD code in the U.S. set.

That is why a patient with purely obsessional OCD gets coded F42.2 or F42.9 rather than something that describes them. It also means a U.S. claim built from an international reference will carry a code that does not exist.

Sources: CDC ICD-10-CM Tabular List, F42 · WHO ICD-10, F42

For the current U.S. code descriptions, work from the CDC ICD-10-CM browser, which carries the official Tabular List and Alphabetic Index, or the NCHS code files. Our ICD-10 code glossary entry covers how the code set is structured.

F42.2: Mixed obsessional thoughts and acts

F42.2 is the ICD-10-CM code for mixed obsessional thoughts and acts.

It is used for OCD presentations involving both obsessions and compulsions. Obsessions are recurrent, intrusive thoughts, urges, or images that cause distress. Compulsions are repetitive behaviors or mental acts that a person feels driven to perform, often in response to an obsession or according to rigid rules.

For example, a patient may experience intrusive fears of contamination and repeatedly wash their hands to reduce distress. Another patient may experience unwanted doubts about having harmed someone and repeatedly check, mentally review, or seek reassurance.

The clinician should document the actual presentation rather than relying on a symptom label alone.

Documentation considerations:

• Describe the intrusive thoughts, urges, or images and the distress associated with them.
• Identify the repetitive behaviors or mental acts and their relationship to the obsessions.
• Document the frequency, duration, and functional impact of symptoms.
• Explain how symptoms interfere with work, school, relationships, daily activities, or treatment participation.
• Include relevant differential diagnoses and the clinical rationale supporting OCD.

The presence of intrusive thoughts alone does not establish F42.2. Likewise, repetitive behaviors are not necessarily compulsions. The assessment should establish the clinical pattern and support the diagnosis.

F42.3: Hoarding disorder

F42.3 is the ICD-10-CM code for hoarding disorder.

Hoarding disorder involves persistent difficulty discarding or parting with possessions, regardless of their actual value, because of a perceived need to save them and distress associated with discarding.

The resulting accumulation may congest and clutter active living areas and substantially interfere with their intended use. The symptoms must be evaluated in context, including their effect on functioning and the applicable diagnostic criteria.

Hoarding disorder is classified within the obsessive-compulsive and related disorders category, but it is not simply another name for OCD.

A patient with hoarding disorder does not automatically have OCD. Conversely, a patient with OCD may have hoarding-related obsessions or compulsions without meeting criteria for a separate hoarding disorder.

Documentation considerations:

• Describe the persistent difficulty discarding possessions.
• Document the perceived need to save items and distress associated with discarding.
• Explain the extent and consequences of accumulation.
• Describe effects on living spaces, safety, relationships, and daily functioning.
• Document whether the presentation is better explained by another medical, psychiatric, or situational condition.

Avoid assigning F42.3 based only on a cluttered home or difficulty organizing possessions. The diagnosis requires clinical assessment of the underlying pattern.

When the clinician establishes hoarding disorder, F42.3 should be considered rather than using F42.9 simply because the presentation falls within the broader obsessive-compulsive and related disorders category.

F42.4: Excoriation (skin-picking) disorder

F42.4 is the ICD-10-CM code for excoriation (skin-picking) disorder.

The condition involves recurrent skin picking that results in skin lesions, with repeated attempts to decrease or stop the behavior. The behavior must cause clinically significant distress or impairment and cannot be better explained by another medical or psychiatric condition.

Skin picking can occur for several reasons. A patient may pick at skin because of a dermatologic condition, a substance-related effect, a psychotic belief, or another cause. The behavior alone does not establish excoriation disorder.

Documentation considerations:

• Describe the recurrent picking behavior and affected areas.
• Document skin lesions or other consequences when present.
• Record attempts to reduce or stop the behavior.
• Describe distress, impairment, and effects on daily functioning.
• Address relevant dermatologic, medical, substance-related, or psychiatric explanations.

F42.4 should not be used as a general code for all repetitive grooming or skin-related behaviors. The clinician must establish the disorder and document the findings supporting it.

If the patient has OCD with skin-picking compulsions but does not meet criteria for a separate excoriation disorder, the clinician should code the established diagnosis rather than automatically assigning F42.4.

F42.8: Other obsessive-compulsive disorder

F42.8 is the ICD-10-CM code for other obsessive-compulsive disorder.

This code is intended for a specified obsessive-compulsive disorder that does not fit another available code in the classification.

The word "other" is important. It indicates that the clinician has identified a specific condition or presentation, but the classification does not provide a more specific code for it.

F42.8 should not be used merely because the documentation is incomplete or because the clinician has not yet determined the diagnosis.

Documentation considerations:

• State the specific diagnosis or presentation.
• Describe the symptoms and clinical findings supporting it.
• Explain how the presentation differs from the conditions represented by other available codes, when relevant.
• Document functional impairment and treatment needs.
• Verify that the diagnosis is appropriately classified under F42.8 in the current ICD-10-CM resources.

For example, a clinician may document a specified obsessive-compulsive presentation that does not meet the classification for another available F42 code. The record should identify that presentation rather than simply state "other OCD."

If the clinician has not established a specific diagnosis, F42.9 may be more appropriate.

F42.9: Obsessive-compulsive disorder, unspecified

F42.9 is the ICD-10-CM code for obsessive-compulsive disorder, unspecified.

It is appropriate when the clinician has established OCD but the documentation does not specify a more particular classification supported by the assessment.

F42.9 is a valid billable code. It is not inherently incorrect, and clinicians should not select a more specific diagnosis simply to obtain reimbursement or authorization.

However, unspecified coding should not be used as a substitute for an adequate diagnostic assessment.

Documentation considerations:

• Clearly identify OCD as the established diagnosis.
• Describe the symptoms supporting the diagnosis.
• Document the severity, frequency, duration, and functional effects of the presentation.
• Include relevant differential diagnoses and clinical reasoning.
• Explain why a more specific classification is not established, when clinically relevant.

An unspecified code does not mean that the clinician can omit the clinical information needed to support treatment.

For example, F42.9 may be appropriate when a clinician has established OCD during an initial assessment but has not yet determined a more specific classification. The record should still describe the patient's presentation and the clinical needs being addressed.

If the record clearly establishes a more specific diagnosis, the code should reflect that supported diagnosis.

How to choose between F42.2, F42.3, F42.8, and F42.9

The choice depends on the diagnosis established by the clinician, not simply on the symptom that appears most frequently in a progress note.

The key distinction is between a symptom, a clinical diagnosis, and a billable code.

A patient may report checking, washing, intrusive thoughts, saving possessions, or skin picking. Those observations help guide the assessment, but they do not independently determine the ICD-10-CM code.

The clinician should establish the diagnosis, document the relevant findings, and use the current code set to select the appropriate code.

OCD documentation and medical necessity

A diagnosis code communicates the condition being treated. It does not, by itself, establish medical necessity for every service or treatment intensity.

For behavioral health claims, documentation should connect the patient's clinical presentation to the service being provided.

This is particularly relevant when the record supports OCD but the claim is for intensive outpatient treatment, partial hospitalization, residential treatment or another service with its own medical-necessity criteria. Behavioral health payers usually frame that question through the ASAM levels of care.

What should the clinical record include?

A clinically useful OCD assessment should address:

Symptoms and diagnostic basis. Describe the obsessions, compulsions, or other symptoms supporting the diagnosis. Include relevant onset, duration, frequency, and course.

Functional impairment. Explain how symptoms affect daily living, work, education, relationships, or participation in treatment.

Severity and treatment needs. Document the patient's current clinical needs and how symptoms affect the treatment plan. Include relevant risk assessment and co-occurring conditions.

Interventions and response. Record the treatment provided, the patient's response, progress toward goals, and the rationale for continuing or modifying care.

Level-of-care rationale. When requesting an intensive service, explain why the requested intensity is appropriate for the patient's documented needs and why a less intensive option would not adequately address them, when applicable.

A diagnosis of OCD may be clinically significant across a range of service settings. The selected code does not independently establish whether outpatient, intensive outpatient or inpatient treatment is appropriate. That comes from the level of care assessment and what the record shows.

Example: F42.9 on an intensive treatment claim

Consider a hypothetical patient with an established OCD diagnosis who is receiving intensive behavioral health treatment because symptoms substantially interfere with daily functioning.

F42.9 may be appropriate if the clinician has not established a more specific classification. But a claim or authorization request supported only by the diagnosis label may not explain why intensive services are needed.

The record should describe the patient's current symptoms, functional limitations, treatment history, required interventions, and clinical rationale for the requested service.

If the clinician has established a more specific diagnosis, the code should reflect that diagnosis. If the diagnosis remains unspecified, the medical-necessity narrative should still be complete.

Do not change F42.9 to F42.2 or F42.8 solely to obtain authorization. Coding specificity must follow the documented clinical diagnosis, not the desired reimbursement outcome.

For related claim issues, see our CO-16 denial code guide, which covers claims missing information or carrying billing errors, and CO-50 for medical-necessity denials.

Assessment instruments and clinical documentation

Clinicians may use structured assessment instruments to support evaluation, track symptoms, and monitor treatment progress.

The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) is one commonly used instrument for assessing OCD symptom severity. It can provide structured information to support clinical assessment and longitudinal monitoring.

However, an assessment score is not an ICD-10-CM diagnosis and does not independently establish a particular F42 code.

The clinician should interpret instrument results alongside the diagnostic interview, clinical history, functional impairment, and applicable diagnostic criteria.

The Y-BOCS is a severity measure, not a code selector. Nothing in ICD-10-CM keys an F42 code to a Y-BOCS band, so a score belongs in the narrative that supports the service, not in the logic that picks the code. That distinction matters most on prior authorization, where a score is useful evidence of severity and useless as a diagnosis.

Common OCD ICD-10 coding mistakes

Frequently asked questions

What is the most common ICD-10 code for OCD?

F42.9 is the code for obsessive-compulsive disorder, unspecified. F42.2 identifies mixed obsessional thoughts and acts. The appropriate code depends on the clinician's diagnosis and the specificity supported by the record.

Is F42 a billable ICD-10-CM code?

No. F42 is a nonbillable category header. A billable code such as F42.2, F42.3, F42.4, F42.8, or F42.9 should be selected as appropriate.

What is the difference between F42.2 and F42.9?

F42.2 identifies mixed obsessional thoughts and acts. F42.9 identifies OCD when the classification is unspecified. F42.2 should be used when supported by the documented diagnosis and applicable coding guidance, not simply because a patient reports intrusive thoughts or repetitive behavior.

Is hoarding disorder coded as OCD?

Hoarding disorder is classified within the obsessive-compulsive and related disorders category, but it is a distinct diagnosis. In U.S. ICD-10-CM, F42.3 identifies hoarding disorder. It should not be assigned automatically to a patient with OCD who saves possessions.

What is the ICD-10 code for skin-picking disorder?

F42.4 is the ICD-10-CM code for excoriation (skin-picking) disorder. The clinician must establish the diagnosis and document the relevant symptoms, impairment, and differential considerations.

Does F42.9 cause an automatic medical-necessity denial?

No. F42.9 is a valid billable code. A payer may request additional documentation or deny a service when the record does not establish medical necessity under its applicable criteria. The outcome depends on the payer's requirements, the benefit, and the clinical documentation.

Is there an ICD-10 code for purely obsessional OCD?

Not in the U.S. code set. WHO ICD-10 has F42.0 for predominantly obsessional thoughts or ruminations, but ICD-10-CM does not include it. A U.S. claim for obsessions-only OCD uses F42.2 or F42.9 depending on what the record establishes.

Why does ICD-10-CM jump from F42 to F42.2?

Because F42.0 and F42.1 exist only in the international classification. ICD-10-CM begins its billable OCD codes at F42.2, which is a common source of confusion when someone is working from a WHO reference.

Do any F42 codes have severity characters?

No. Unlike the eating disorder codes, which were subdivided by severity in 2023, the F42 codes have no severity level. Severity belongs in the narrative, not in the code.

Can a clinician select F42.8 to obtain authorization?

No. F42.8 should reflect a specified obsessive-compulsive disorder that does not fit another available code. A clinician should not choose a more specific diagnosis solely to obtain authorization or reimbursement.

Sources and coding references

1. Centers for Disease Control and Prevention, National Center for Health Statistics. ICD-10-CM. cdc.gov
2. Centers for Disease Control and Prevention, National Center for Health Statistics. ICD-10-CM browser: Tabular List and Alphabetic Index. icd10cmtool.cdc.gov
3. National Center for Health Statistics. ICD-10-CM FY2027 code files. ftp.cdc.gov
4. National Center for Health Statistics. ICD-10-CM Official Guidelines for Coding and Reporting, FY2027. ftp.cdc.gov
5. World Health Organization. ICD-10, F42: Obsessive-compulsive disorder. icd.who.int

Related guides: Schizophrenia ICD-10 codes · F50.9 eating disorder, unspecified · Autism ICD-10 code · Substance use disorder ICD-10 codes · ICD-10 code glossary entry · CO-16 denial code

Every code in this article was checked against the ICD-10-CM code set in effect on September 28, 2026. Codes and guidelines change each October 1. This is educational content, not a substitute for the current Tabular List, Alphabetic Index and your payer's requirements.