title: Psychometric modeling of abuse and dependence symptoms across six illicit substances indicates novel dimensions of misuse.
abstract: OBJECTIVE
  This study explored the factor structure of DSM III-R/IV symptoms for substance abuse and dependence across six illicit substance categories in a population-based sample of males.
  
  
  METHODS
  DSM III-R/IV drug abuse and dependence symptoms for cannabis, sedatives, stimulants, cocaine, opioids and hallucinogens from 4179 males born 1940-1970 from the population-based Virginia Adult Twin Study of Psychiatric and Substance Use Disorders were analyzed. Confirmatory factor analyses tested specific hypotheses regarding the latent structure of substance misuse for a comprehensive battery of 13 misuse symptoms measured across six illicit substance categories (78 items).
  
  
  RESULTS
  Among the models fit, the latent structure of substance misuse was best represented by a combination of substance-specific factors and misuse symptom-specific factors. We found no support for a general liability factor to illicit substance misuse.
  
  
  CONCLUSIONS
  Results indicate that liability to misuse illicit substances is drug class specific, with little evidence for a general liability factor. Additionally, unique dimensions capturing propensity toward specific misuse symptoms (e.g., tolerance, withdrawal) across substances were identified. While this finding requires independent replication, the possibility of symptom-specific misuse factors, present in multiple substances, raises the prospect of genetic, neurobiological and behavioral predispositions toward distinct, narrowly defined features of drug abuse and dependence.
authors.affiliation: Center for Biomarker Research and Precision Medicine, Virginia Commonwealth University School of Pharmacy, Brisbane, Australia. Electronic address: slclark2@vcu.edu.
authors.forename: Shaunna L
authors.initials: SL
authors.lastname: Clark
authors.affiliation: Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Brisbane, Australia; Queensland Institute of Medical Research, Brisbane, Australia.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Gillespie
authors.affiliation: Center for Biomarker Research and Precision Medicine, Virginia Commonwealth University School of Pharmacy, Brisbane, Australia.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Adkins
authors.affiliation: Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Brisbane, Australia.
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Kendler
authors.affiliation: Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Brisbane, Australia.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Neale
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid; D002188:Cannabis; D000697:Central Nervous System Stimulants; D003042:Cocaine; D005163:Factor Analysis, Statistical; D006213:Hallucinogens; D006801:Humans; D006993:Hypnotics and Sedatives; D013287:Illicit Drugs; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000453:epidemiology*; D014427:Twins / Q000706:statistics & numerical data; D014768:Virginia / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D000697:Central Nervous System Stimulants; D006213:Hallucinogens; D006993:Hypnotics and Sedatives; D013287:Illicit Drugs; D003042:Cocaine
keywords: Cannabis; Cocaine; DSM; Dependence; Factor analysis; Opioids