Table 1.

Sample characteristics, design, and outcomes.

Authors (year)	Approach type	Sample	Treatment type	Design	Assessment tool	Predictors evaluated	Conclusions
Beattie & Longabaugh (1999)	Network predicting outcome	152 AUD	Outpatient	Longitudinal	IPA Procidano and Heller’s (1983) 40-item Perceived Social Support self-report instrumenta	Alcohol-specific support General supporta	Both general and alcohol-specific social support predicted higher PDA shortly after Tx Alcohol-specific support continued to predict PDA in the long term
Broome, Simpson, & Joe (2002)	Network predicting outcome	748 AUD/SUD	Short term inpatient	Longitudinal	Questions formulated for this study specifically	Deviant peer network (network member used drugs/drank heavily/had been arrested) Cohabitants supportive of abstinence Cohabitants with SUD	Deviant network and living with user/drinker predicted use of cocaine and frequent drinking Support for abstinence at home reduced odds of cocaine use
Groh et. al (2007)	Network predicting outcome	897 AUD/SUD	Residential (OH)	Longitudinal	IP	General support (family, friends) Abstinence-specific support (family, friends)	General support from friends interacted with length of stay to predict less alcohol use 90 days before follow up
Groh et. al (2011)	Network predicting outcome	897 AUD/SUD	Residential (OH)	Longitudinal	IP	Support of drinking Drinking Bx of network General support	Only drinking Bx of network predicted drinking at 4 months
Litt et. al (2009)	Tx predicting network change	210 AUD	Outpatient	Longitudinal	IPA	Tx approach (network support, network support + contingency, or case management)vs. social, Bx, and attitudinal support for drinking; Bx and attitudinal support for abstinence	Bx Support for drinking decreased in all Tx Groups Bx support for abstinence increased for both NS interventions at 15 months; dropped for NS+C but rose for CM at 27 months Attitudinal support for abstinence higher over time for both NS and NS+C NS –number of abstinent friends increased then leveled at 15 months; NS+C declined at 15
Longabaugh et. al (1995)	[network indicating effective Tx approach]	229 AUD	Outpatient	Longitudinal	IPA	Interaction between network support of alcohol involvement/abstinence, investment in social network, and Tx approach (extended relationship enhancement, brief broad spectrum, and extended cognitive behavioral)	Participants with low support for abstinence or low social investment, but not both had greatest PDA with ERE BBS treatment was found to be more effective for patients with either low investment in an unsupportive network or high investment in a supportive network.
Longabaugh et. al (2010)	Network predicting outcome	1,373 AUD	Outpatient	Longitudinal	IPA	Network drinking Response to participant drinking General support Support of Tx Amount of contact Social investment	Alcohol specific support predicted more days abstinent during and following Tx and fewer HDD following Tx Network opposition to drinking was increasingly predictive of higher PDA and lower PHDD Daily support was increasingly related to more HDD and fewer days abstinent following Tx
Min et. al (2013)	Tx predicting network change	377 women with SUD	Residential (n=119) Outpatient (n=258)	Longitudinal	EgoNet	Tx approach (residential or outpatient)	Women in residential had more substance using alters in network Only residential showed within group time effect, with significant increase in the number of Tx-related alters and decrease in substance using alters
Mohr et. al (2001)	Network predicting outcome Tx predicting network change	1,726 AUD	Outpatient	Longitudinal,	IPA	Proportion of non-drinking and drinking friends in the network Amount of contact with drinking and non-drinking friends Liking and importance of drinking and non-drinking friends completion of Tx	Participants who maintained high proportion drinking friends had more DDD at follow up than those who decreased proportion of drinking friends; Increase in proportion of non-drinking friends predicted fewer DDD at follow up Higher proportion of important drinking friends at baseline predicted more DDD at follow up Increased importance of non-drinking friends predicted PDA at follow up Proportion of drinkers decreased while proportion of non-drinkers increased post-Tx Contact with both drinking and non-drinking friends decreased Liking and importance of both drinking and non-drinking friends increased
Stout et. al (2012)	Network predicting outcome	1,726 AUD	Outpatient	Longitudinal,	IPA	Propensity score: total network size, number of heavy drinkers, and number of abstainers in the network Number of pro-abstinence and pro-drinking network members	At months 15 and 39: No effect for propensity stratification Number of pro-drinkers predicted poorer outcomes for PDA and DDD Number of pro-abstainers predicted higher PDA
Tracy et. al (2012)	Tx predicting network change	242 women with SUD	Outpatient	Cross-sectional	EgoNet	4 treatment stages (engagement, persuasion, active treatment, relapse prevention)	Networks in active treatment stage included more network members from Tx programs or 12-Step Neither the type nor amount of social support differed across Tx stages Networks of women in active Tx were less connected, as indicated by a higher number of components Networks of women in the persuasion stage had a higher degree of centralization, as indicated by networks dominated by people with the most ties
Wu & Witkiewitz (2008)	Network predicting outcome [Network indicating effective Tx approach]	952 AUD	Outpatient	Longitudinal	IPA	Network support for drinking Interaction between network support for drinking and Tx type (Twelve Step Facilitation, Motivational Enhancement Therapy, Cognitive Behavioral Therapy)	More network support for drinking predicted more drinking consequences, but only for participants assigned to MET or CBT
Zywiak, Longabaugh, & Wirtz (2002)	Network predicting outcome [Network indicating effective Tx approach]	952 AUD	Outpatient	Longitudinal	IPA	Network size Size of daily network Network importance Network drinking status Network drinking frequency Network maximum drinks per drinking day Percentage of heavy drinkers Percentage of abstainers and recovering alcoholics Most support for drinking Least support for drinking Average support for drinking Interaction between pre-Tx IPA and Tx type (Twelve Step Facilitation, Motivational Enhancement Therapy)	Larger daily networks and more abstainers/recovering alcoholics in networks predicted higher PDA and lower monthly volume of alcohol consumed Patients with a higher network drinking frequency did better (in terms of DDD and PDA) in Twelve Step Facilitation than in Motivational Enhancement Therapy
Zywiak et. al (2009)	Network predicting outcome Bx change predicting network change	141 cocaine dependent	Residential	Longitudinal	IPDA	Substance involvement of network General/Tx support Support for abstinence Size of daily network Size of network Importance of most important people Abstinence at 6 months	Size of daily network predicted less drinking, less drug use, and less problem severity post-Tx Network substance involvement decreased for those who stayed abstinent

Notes. Network variables predicting outcome listed by numerals, Bx change or Tx variables predicting network change listed by letters. PDA = percentage of days abstinent; DDD= drinks per drinking day, HDD= heavy drinking days, PHDD= percentage of heavy drinking days.

^aProcidano and Heller’s (1983) 40-item Perceived Social Support self-report instrument not collected as an ego network measure.