Can Conduct Disorder Be Diagnosed in Individuals Under 18 Years Old?
Yes, conduct disorder is specifically a childhood and adolescent diagnosis that can only be made in individuals younger than 18 years of age. Once a person reaches 18 years or older, the diagnosis transitions to antisocial personality disorder if the pattern of behavior continues. 1, 2
Age-Specific Diagnostic Criteria
Conduct disorder is defined as a psychiatric syndrome that most commonly occurs in childhood and adolescence, characterized by aggression toward people or animals, destruction of property, deceitfulness or theft, and serious violations of rules. 3
The disorder typically emerges in childhood or adolescence and affects approximately 3% of school-aged children, with males affected twice as frequently as females. 2
At least three symptoms must have been present in the past 12 months, with at least one symptom present in the past six months to establish the diagnosis. 3
Age-Based Subtypes
Conduct disorder is subtyped according to age at onset: childhood-onset (before age 10) versus adolescent-onset (age 10 or later). 2
Earlier age at onset conveys a significantly poorer prognosis, with a three-fold increased risk of progression to conduct disorder in children with early-onset oppositional defiant disorder. 1
Approximately 30% of children with oppositional defiant disorder will progress to conduct disorder, and ultimately about 10% of the baseline cohort with ODD will develop antisocial personality disorder in adulthood. 1
Critical Diagnostic Considerations
Boys are more likely to exhibit conduct disorder comorbid with oppositional defiant disorder, while the disorder commonly co-occurs with attention-deficit/hyperactivity disorder (ADHD) in both sexes. 1
Disruptive disorders are common in male teenagers, with as many as one-third of male adolescents with severe behavioral problems meeting criteria for conduct disorder, often comorbid with mood, anxiety, or substance abuse diagnoses. 1
The diagnosis should be distinguished from oppositional defiant disorder alone: conduct disorder involves more severe antisocial behaviors including aggression, theft, vandalism, and serious rule violations, whereas ODD primarily involves defiant and hostile behavior toward authority figures. 1, 4
Important Clinical Pitfall
DSM criteria preclude formally making a diagnosis of conduct disorder in the presence of antisocial personality disorder criteria (which applies to adults 18 years and older), though the literature is not entirely clear whether ODD and conduct disorder can be comorbid. 1
Conduct disorder alone is an extreme rarity—multiple comorbid disorders are almost always the rule rather than the exception, requiring comprehensive assessment using structured interviews and rating scales covering all psychiatric disorders. 5