title: Cocaine dependence and concurrent marijuana use: a comparison of clinical characteristics.
abstract: OBJECTIVE
  Marijuana is the most commonly used illicit substance, yet among the least studied in medication development research. Cocaine-dependent individuals frequently also use marijuana; however, little is known about the effect of this combined use on treatment presentation.
  
  
  METHODS
  Marijuana use was assessed in 1183 individuals seeking outpatient treatment for cocaine dependence. Based on past 30 days of use, the sample was divided into three groups: (1) patients reporting no recent marijuana use (n = 634); (2) occasional use (n = 403); (3) and frequent concurrent marijuana use (n = 146). Differences on baseline measures of substance use, addiction severity (ASI), psychopathology, and sociodemographic characteristics were examined as a function of level of marijuana use.
  
  
  RESULTS
  Frequent marijuana users were more likely to be female, Caucasian, and younger than other groups. Cocaine-dependent patients with frequent marijuana use also used more cocaine and alcohol, and reported more medical, legal, and psychiatric problems, including antisocial personality disorder.
  
  
  CONCLUSIONS
  Cocaine-dependent patients with frequent marijuana use present for treatment with more severe impairment. Accounting for this heterogeneity among participants may improve treatment outcome.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Texas, Houston, Texas, USA. Jan.A.Lindsay@uth.tmc.edu
authors.forename: Jan A
authors.initials: JA
authors.lastname: Lindsay
authors.forename: Angela L
authors.initials: AL
authors.lastname: Stotts
authors.forename: Charles E
authors.initials: CE
authors.lastname: Green
authors.forename: David V
authors.initials: DV
authors.lastname: Herin
authors.forename: Joy M
authors.initials: JM
authors.lastname: Schmitz
mesh_terms: D000328:Adult; D000367:Age Factors; D000987:Antisocial Personality Disorder / Q000150:complications*; D019970:Cocaine-Related Disorders / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation; D017831:Diagnosis, Dual (Psychiatry); D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000150:complications / Q000453:epidemiology*; D008875:Middle Aged; D044469:Racial Groups / Q000706:statistics & numerical data; D012720:Severity of Illness Index; D012737:Sex Factors; D016320:Substance Abuse Treatment Centers