F91.9

Conduct disorder, unspecified

Conduct disorder, unspecified, is a psychiatric diagnosis classified within the category of behavioral and emotional disorders with onset usually occurring in childhood and adolescence. It represents a repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate societal norms or rules are violated. This diagnosis is used when a patient's behavioral patterns meet the general criteria for a conduct disorder—exhibiting behaviors such as aggression, destruction of property, or deceitfulness—but there is either insufficient information to categorize the condition into a more specific subtype (such as childhood-onset or adolescent-onset) or the clinical presentation does not perfectly align with the existing specific categories. Individuals with this disorder often experience significant social, academic, and occupational impairment. It is frequently comorbid with other neurodevelopmental and mental health conditions, including attention-deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and mood or substance use disorders.

Clinical Symptoms

  • Aggression toward people and animals
  • Frequent initiation of physical fights
  • Use of weapons that can cause serious physical harm
  • Physical cruelty to people
  • Physical cruelty to animals
  • Theft while confronting a victim (e.g., mugging, armed robbery)
  • Forcing someone into sexual activity
  • Deliberate fire setting with the intention of causing serious damage
  • Deliberate destruction of the property of others
  • Breaking into someone else's house, building, or car
  • Frequent lying to obtain goods or favors or to avoid obligations
  • Shoplifting or stealing without confronting a victim
  • Staying out at night despite parental prohibitions (beginning before age 13)
  • Running away from home overnight at least twice
  • Frequent school truancy (beginning before age 13)
  • Lack of remorse or guilt regarding misbehavior
  • Callousness and lack of empathy for the feelings of others
  • Unconcern about performance in school or at work
  • Shallow or deficient affect (not expressing feelings or emotions to others)

Common Causes

  • Genetic predisposition and family history of antisocial behavior
  • Neurobiological deficits in brain areas responsible for impulse control and emotional regulation
  • Adverse childhood experiences (ACEs) including physical or sexual abuse
  • Parental neglect or inconsistent/harsh disciplinary practices
  • Exposure to domestic violence or chronic community violence
  • Maternal substance abuse or tobacco use during pregnancy
  • Early childhood exposure to lead or other neurotoxins
  • Association with delinquent peer groups
  • Low socioeconomic status and lack of access to supportive resources
  • Chronic family instability or frequent changes in primary caregivers

Documentation & Coding Tips

Distinguish between conduct-related behaviors and standard developmental defiance by documenting persistent patterns of violating social norms or the rights of others.

Example: Patient exhibits a six-month history of repetitive patterns involving theft of items from school lockers and physical altercations with peers. These behaviors represent a significant departure from age-appropriate societal norms and indicate a persistent conduct disturbance. Risk Adjustment: Chronic behavioral disorder impacting social and educational functioning.

Billing Focus: Documentation of duration (greater than 6 months) and specific categories of behavior (aggression to people, destruction of property) to support code selection.

When specific onset (childhood vs. adolescent) is not yet clear, utilize F91.9 but document the intent to clarify the subtype in subsequent visits.

Example: Initial psychiatric evaluation of 14-year-old male presenting with recent arrest for vandalism and history of truancy. Onset age of behaviors is currently unknown as family history is limited. Assessment: Conduct disorder, unspecified (F91.9). Billing Focus: Use of unspecified code during initial diagnostic phase while history is being gathered.

Billing Focus: Clarification of why a more specific code (F91.1 or F91.2) cannot be assigned based on current medical record data.

Clearly document the impact of the conduct disorder on the patient's functional domains including school performance and family relationships.

Example: The patient's conduct disturbances, specifically frequent rule violations and aggressive posturing, have resulted in three school suspensions this semester. Family dynamics are strained with the patient refusing to follow household rules. Risk Adjustment: Behavioral severity level is high, requiring intensive outpatient management and frequent monitoring.

Billing Focus: Functional impairment documentation supports medical necessity for higher-level E/M services or prolonged psychotherapy sessions.

Identify and document co-occurring conditions such as ADHD or Mood Disorders, as these significantly influence the treatment plan for F91.9.

Example: Patient diagnosed with conduct disorder, unspecified, complicated by comorbid ADHD, combined type (F90.2). The impulsivity of ADHD exacerbates the aggressive outbursts seen in the conduct disorder. Billing Focus: Dual diagnosis requires complex medical decision making involving multiple medication management strategies.

Billing Focus: Linking comorbidities to the primary diagnosis to justify the complexity of the clinical encounter.

Note the presence or absence of limited prosocial emotions, such as lack of remorse or callousness, even when using the unspecified code.

Example: Current presentation for conduct disorder, unspecified, is notable for a significant lack of remorse regarding the harm caused to peers during physical fights. The patient demonstrates a callous disregard for the feelings of others. Billing Focus: Clinical specificity regarding emotional traits supports future transition to more specific ICD-10-CM codes.

Billing Focus: Detailed clinical descriptions help justify the need for specialized behavioral health interventions.

Relevant CPT Codes

Related Diagnoses

Hierarchy