Conduct disorders (F91) ICD-10-CM
The F91 code range covers conduct disorders with 7 ICD-10-CM diagnosis codes. 6 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Codes in the F91 Range 7 codes · 6 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the F91 range.
Conduct Disorder
A repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate societal norms or rules are violated. These behaviors include aggressive conduct that causes or threatens physical harm to other people or animals, nonaggressive conduct that causes property loss or damage, deceitfulness or theft, and serious violations of rules. The onset is before age 18. (From DSM-IV, 1994)
Oppositional Defiant Disorder
A repetitive and persistent pattern of behavior that develops in childhood and is characterized as recurrent disobedient, overall negative or agitated mood, a quarrelsome attitude or being vengeful toward authority figures. Unlike in conduct disorder defiant behaviors in oppositional defiant disorders typically do not involve aggression, destruction, theft, or deceit. Oppositional defiant disorder, CONDUCT DISORDER and ATTENTION DEFICIT AND HYPERACTIVITY DISORDER sometimes co-occur.
About the F91 Code Range
Conduct disorder is a repeated pattern of behavior that violates others’ rights or major rules expected for a person’s age. It can involve aggression, property damage, theft or serious rule-breaking.
F91 sits among behavioral and emotional disorders that usually begin in childhood or adolescence. Its subdivisions separate conduct disorder confined to the family context (F91.0) from childhood-onset (F91.1) and adolescent-onset (F91.2) types. They also identify oppositional defiant disorder (F91.3), other conduct disorders (F91.8) and unspecified conduct disorder (F91.9).
Questions About This Page
How many billable codes are in the F91 range?
Of the 7 codes in this range, 6 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the F91 range classify?
The range classifies conduct disorders. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
