Is the Continuity of Externalizing Psychopathology the Same in Adolescents and Middle–Aged Adults? A Test of the Externalizing Spectrum’s Developmental Coherence

Externalizing psychopathology (EXT) is a framework for understanding diagnostic comorbidity and etiology of antisocial and
substance-use behaviors. EXT indicates continuity in adulthood but the structure of adolescent EXT is less clear. This report
examines whether adolescent EXT is trait-like, as has been found with adults, or categorical. We use tests of measurement
invariance to determine how diagnostic indicators of EXT differ in adolescents compared to adults. The EXT measures employed
were DSM-IIIR diagnoses of adult antisocial behavior, conduct disorder, and alcohol, marijuana, and drug dependence. Latent
trait, latent class, and hybrid models were fit to two separate data sets: 2,769 seventeen-year-old adolescents and 2,619
adults from the Minnesota Twin Family Study. The best model in both samples was a single-trait LT model. Parameters from the
adolescent and adult models were equivalent for all disorders except alcohol dependence. It appears that EXT in adolescence
can be accurately represented by a single-trait model, and the measurement properties of EXT are similar during these time
periods with the exception of alcohol dependence.