title: Heterogeneity of stimulant dependence: a national drug abuse treatment clinical trials network study.
abstract: We investigated the presence of DSM-IV subtyping for dependence on cocaine and amphetamines (with versus without physical dependence) among outpatient stimulant users enrolled in a multisite study of the Clinical Trials Network (CTN). Three mutually exclusive groups were identified: primary cocaine users (n = 287), primary amphetamine users (n = 99), and dual users (cocaine and amphetamines; n = 29). Distinct subtypes were examined with latent class and logistic regression procedures. Cocaine users were distinct from amphetamine users in age and race/ethnicity. There were four distinct classes of primary cocaine users: non-dependence (15%), compulsive use (14%), tolerance and compulsive use (15%), and physiological dependence (tolerance, withdrawal, and compulsive use; 56%). Three distinct classes of primary amphetamine users were identified: non-dependence (11%), intermediate physiological dependence (31%), and physiological dependence (58%). Regardless of stimulants used, most female users were in the most severe or the physiological dependence group. These results lend support for subtyping dependence in the emerging DSM-V.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina, USA. litzy.wu@duke.edu
authors.forename: Li-Tzy
authors.initials: LT
authors.lastname: Wu
authors.forename: Dan G
authors.initials: DG
authors.lastname: Blazer
authors.forename: Ashwin A
authors.initials: AA
authors.lastname: Patkar
authors.forename: Maxine L
authors.initials: ML
authors.lastname: Stitzer
authors.forename: Paul G
authors.initials: PG
authors.lastname: Wakim
authors.forename: Robert K
authors.initials: RK
authors.lastname: Brooner