title: P300 amplitude, externalizing psychopathology, and earlier- versus later-onset substance-use disorder.
abstract: P300 amplitude predicts substance use or disorder by age 21. Earlier- versus later-onset substance disorders may reflect different levels of an externalizing psychopathology dimension. P300 in adolescence may not be as strongly related to later-onset substance problems as it is to earlier-onset ones. In the present study, visual P300 amplitude was measured at age 17 in a community-representative sample of young men. Substance and externalizing disorders were assessed at approximately ages 17, 20, and 24. Earlier-onset (by age 20) substance disorder was associated with higher rates of externalizing disorders than were later-onset problems. P300 amplitude was reduced in subjects with earlier-onset substance disorders, relative to later-onset and disorder-free subjects. Amplitude was also reduced in subjects with an externalizing disorder but no substance disorder. Earlier-onset subjects had reduced P300, even in the absence of an externalizing disorder. The results could not be attributed to a concurrent disorder or to recent substance use at the time of the P300 recording. The findings are consistent with P300 indexing an externalizing spectrum. Earlier-onset substance disorders are more strongly related to P300 and externalizing than are later-onset problems.
authors: Department of Psychology, University of British Columbia, Vancouver, BC, Canada. scarlson@psych.ubc.ca
authors: Scott R
authors: SR
authors: Carlson
authors: Megan E
authors: ME
authors: McLarnon
authors: William G
authors: WG
authors: Iacono
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000987:Antisocial Personality Disorder / Q000175:diagnosis / Q000503:physiopathology*; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000523:psychology*; D014427:Twins / Q000523:psychology