title: Longitudinal Dynamics of Substance Use and Psychiatric Symptoms in Count Data with Zero Inflation.
abstract: We examine the dynamics of substance use and psychiatric symptoms from childhood to adolescence using a longitudinal study of Mexican-origin families (N = 674). We present a longitudinal model capturing the trajectories of substance use and psychiatric symptoms (depression, conduct disorder), as well as the interrelations between these trajectories over time. Such a model is an extension of latent change score models designed to account for the occurrence of psychiatric symptoms while also accommodating a large amount of zeros for nonoccurrence and characterizing the changes over time in the count data. We compare this model with a more traditional approach based on a log transformation of the data. We describe differences between these approaches and highlight the benefits of using the two-part model when the data include a large amount of zeros for nonoccurrence of the behavior.
authors.affiliation: a University of California , Davis.
authors.forename: Emilio
authors.initials: E
authors.lastname: Ferrer
authors.affiliation: a University of California , Davis.
authors.forename: Rand D
authors.initials: RD
authors.lastname: Conger
authors.affiliation: a University of California , Davis.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Robins
mesh_terms: D000293:Adolescent; D000465:Algorithms; D002140:California / Q000453:epidemiology; D002648:Child; D019955:Conduct Disorder / Q000453:epidemiology; D003627:Data Interpretation, Statistical; D003863:Depression / Q000453:epidemiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D017058:Mexican Americans; D015233:Models, Statistical; D015999:Multivariate Analysis; D015995:Prevalence; D012737:Sex Factors; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000523:psychology*
keywords: Longitudinal data analysis; categorical outcome analyses; substance use