ICD-10 Code F91.1 – Conduct disorder, childhood-onset type (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F91.1 – Conduct disorder, childhood-onset type
What it is
F91.1 identifies conduct disorder with onset before age 10. Use it when the record shows a persistent pattern of behavior that violates rules, rights, or social expectations beginning in childhood.
Clinical signs
Typical features include aggression, deceitfulness, serious rule-breaking, or destruction of property. Clinical features vary; refer to documentation, and confirm that symptoms began in childhood.
When to use this code
Use F91.1 when the clinician documents conduct disorder and specifies childhood onset. It fits outpatient, inpatient, or behavioral health records that clearly state the diagnosis. If the onset age is unclear, check documentation before coding.
Do not use for
Do not use this code for oppositional behavior without a conduct disorder diagnosis. Do not assign it when the record describes adolescent-onset conduct disorder or another disruptive behavior condition instead.
Coding tip
Look for explicit wording such as “childhood-onset” or onset before age 10 before selecting F91.1.