title: Social network moderators of naltrexone and behavioral treatment effects on heavy drinking in the COMBINE study.
abstract: BACKGROUND
  Oral naltrexone is an efficacious medication for treatment of alcohol dependence, but small effect sizes and variability in outcomes suggest the presence of person-level moderators of naltrexone response. Identification of contextual or psychosocial moderators may assist in guiding clinical recommendations. Given the established importance of social networks in drinking outcomes, as well as the potential effects of naltrexone in reducing cue reactivity which may be especially important among those with more heavy drinkers and more alcohol cues in their networks, we examined pretreatment social network variables as potential moderators of naltrexone treatment effects in the COMBINE study.
  
  
  METHODS
  The sample included all COMBINE study participants in medication conditions with full data on the Important People Inventory (IPI) and covariates at intake (N = 1,197). The intake IPI assessed whether participants had any frequent drinkers in their network and the average frequency of contact with these drinkers. The effects of treatment condition, pretreatment network variables, and their interactions on percent heavy drinking days were tested in hierarchical linear models, controlling for demographics and baseline clinical covariates.
  
  
  RESULTS
  In treatment conditions involving medical management and combined behavioral intervention (CBI), the effects of active naltrexone on heavy drinking were significantly greater for individuals with frequent drinkers in their network (z = -2.66, p < 0.01) and greater frequency of contact with those drinkers (z = -3.19, p < 0.01). These network variables did not moderate the effects of active naltrexone without CBI.
  
  
  CONCLUSIONS
  When delivered in conjunction with behavioral interventions, naltrexone can be more potent for alcohol-dependent adults who have greater contact with frequent drinkers prior to treatment, which may indicate patterns of environmental exposure to alcohol. Contextual, social risk factors are a potential avenue to guide personalized treatment of alcohol dependence.
authors.affiliation: Department of Family Medicine, University of California, Los Angeles, Los Angeles, California.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Worley
authors.forename: Katie
authors.initials: K
authors.lastname: Witkiewitz
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Brown
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Kivlahan
authors.forename: Richard
authors.initials: R
authors.lastname: Longabaugh
mesh_terms: D000328:Adult; D000428:Alcohol Drinking; D000437:Alcoholism / Q000188:drug therapy / Q000628:therapy*; D001521:Behavior Therapy; D003131:Combined Modality Therapy; D066249:Craving / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009271:Naltrexone / Q000627:therapeutic use*; D009292:Narcotic Antagonists / Q000627:therapeutic use; D012944:Social Support; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D009292:Narcotic Antagonists; D009271:Naltrexone
keywords: Alcohol Dependence; Moderators; Naltrexone; Pharmacotherapy; Social Network