ICD-10 Code F91 – Conduct disorders (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F91 – Conduct disorders
What it is
F91 identifies conduct disorders, a group of behavioral conditions marked by a persistent pattern of violating rules or the rights of others. Use this code when documentation names a conduct disorder without a more specific subtype.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported signs include aggression, serious rule breaking, deceitfulness, destruction of property, and repeated violation of age-appropriate social norms.
When to use this code
Use F91 when the provider documents conduct disorder and does not specify a more detailed category. It may also fit charted assessments describing ongoing disruptive behavior that meets diagnostic criteria for a conduct disorder. Check documentation for the exact subtype and any associated severity.
Do not use for
Do not use F91 for isolated misbehavior, oppositional behavior without conduct disorder, or conditions better documented as another mental health diagnosis. If the record is unclear, check documentation.
Coding tip
Always code the most specific conduct disorder documented, and confirm whether the provider specifies childhood-onset, adolescent-onset, or another subtype.