Interpersonal Styles, Peer Relationships, and Outcomes in SUD Treatment

Substance use disorders (SUDs) are highly prevalent in veteran populations. Among US veterans of the conflicts in Iraq and Afghanistan, for example, approximately one in ten have been diagnosed with an SUD (Seal et al., 2011). Social and interpersonal factors play a key role in the onset and course of SUDs (Galea, Nandi, & Vlahov, 2004; Moos, 2007). Among veterans, limited social support is associated with hazardous drinking (Scott et al., 2013). Social factors are also associated with the development of mental health problems closely linked with SUDs, such as posttraumatic stress disorder and depression (Petrakis, Rosenheck, & Desai, 2011; Smith, Benight, & Cieslak, 2013). Although prior research demonstrates the critical role of social support in SUDs, few studies examine how interpersonal functioning may lead to better or worse outcomes. The current study sought to elucidate the effect of interpersonal styles on SUD outcomes among veterans in residential treatment.

Interpersonal Relationships and SUDs
SUDs often develop in the context of poor relationships with family (Galea et al., 2004) and associations with substance-using peers. Moreover, interpersonal stress may precipitate relapse (Leach & Kranzler, 2013). Interpersonal relationships are also a primary component of successful SUD interventions (Moos, 2007). For example, developing a strong social support network is a mechanism of change for participants involved in mutual-aid groups such as Alcoholics Anonymous (AA; Groh, Jason, & Keys, 2008). Social support also leads to better outcomes in formal SUD treatment (Kidorf et al., 2005; Knight, Wallace, Joe, & Logan, 2001). Social support networks consisting of sober friends and family are a robust predictor of sustained abstinence (Litt, Kadden, Tennen, & Kabela-Cormier, 2016; Stout, Kelly, Magill, & Pagano, 2012).
Developing relationships with peers in treatment is an effective way to enhance social support networks. For example, new social contacts made during recovery are more likely to be “clean and sober” than non-treatment-seeking friends (Knight et al., 2001), and the number of people in individuals’ social networks who oppose drinking is associated with more days abstinent and fewer heavy drinking days four months after the end of treatment (Longabaugh, Wirtz, Zywiak, & O’Malley, 2010). Social support networks formed in mutual-aid groups such as AA (Kaskutas, Bond, & Humphreys, 2002), as well as those formed in formal treatment programs (Knight et al., 2001), are also related to better SUD outcomes.

Interpersonal Styles
What influences the development of social support with peers in treatment? One factor may be problematic interpersonal styles, or difficulties relating to others effectively. The interpersonal circumplex is a well-studied framework to examine such problems. As described by Wiggins (1979), the interpersonal circumplex hypothesizes that problematic interpersonal styles (or “interpersonal problems”) lay on a circular continuum. This continuum is bisected by two orthogonal lines representing underlying dimensions of personality: a vertical line representing dominance, and a horizontal line representing affiliation. Different types of interpersonal styles can be thought of as a specific “blend” of either dominance or affiliation. The Inventory of Interpersonal Problems-Circumplex version (IIP-C) was developed and later validated to assess interpersonal characteristics and behaviors (Alden, Wiggins, & Pincus, 1990).
The IIP-C has been used to describe interpersonal styles in a variety of clinical populations (Barrett & Barber, 2007; Hartmann, Zeeck, & Barrett, 2010; Newman, Jacobson, Erickson, & Fisher, 2017). Despite its relevance, to our knowledge only one study has examined interpersonal styles among people diagnosed with SUDs (Matano & Locke, 1995), and it did not examine how interpersonal styles may relate to outcomes. This omission is critical given the well-established connections between interpersonal functioning and SUDs.

The Current Study
Because social support is a key component in successful SUD treatment, it is important to examine factors which may inhibit the development of strong interpersonal relationships among veterans. The current study builds on prior work by assessing interpersonal styles among a sample of US veterans in residential SUD treatment. Treatment in a residential setting is ideal for examining interpersonal styles among people with SUDs—while in residential treatment, peers interact with one another for most of the day, nearly every day. Residents have contact with peers in both formal treatment activities as well as informal social and recreational activities. Residential treatment settings offer many opportunities for both the development of close relationships as well as the emergence of problematic interpersonal styles.
We examined three research questions: Which interpersonal styles do veterans in residential SUD treatment exhibit; do interpersonal styles at the beginning of residential SUD treatment predict long-term SUD outcomes after discharge; and if so, does the quality of relationships with peers in treatment mediate this association?
We hypothesized that interpersonal styles would predict poor outcomes after discharge, such that more problematic interpersonal styles at the outset of treatment would predict a greater number of SUD symptoms assessed twelve months after discharge from treatment. We also hypothesized that the relationship between interpersonal styles and SUD symptoms would be mediated by poor relationship quality with peers in residential treatment.

Methods
Sample and Procedures
Participants were military veterans enrolled in residential SUD treatment at a Veterans Affairs (VA) medical center. Veterans were involved in treatment approximately seven hours per day, five days per week, in both individual and group-based activities. Treatment interventions were abstinence-based and took a combined cognitive behavioral therapy (CBT) and Twelve Step facilitation (TSF) approach.
Upon entry into treatment, residents were invited to participate in a research study on personality and substance use through announcements and fliers. Research assistants scheduled in-person baseline assessments with interested veterans (n=200). In this study, we included only participants who reported drug and/or alcohol use and endorsed at least one SUD symptom in the twelve months prior to treatment entry (n=189). Of these, 96.2 percent were male, and 46.0 percent identified as non-Hispanic white, 30.7 percent as African American, 12.7 percent as Hispanic or Latino/a, 4.2 percent as Asian, 1.6 percent as Native American, and 4.8 percent as another race/ethnicity. Mean age was 49.9 years (range: twenty-five to seventy-seven years). Based on the Structured Clinical Interview for Axis I Disorders (SCID-I; First, Spitzer, Gibbon, & Williams, 2002), 73.5 percent of the sample met criteria for an alcohol use disorder and 67 percent met criteria for a drug use disorder.
Participants completed assessments at baseline, one month into treatment (n=160, 84.7 percent retention rate), and twelve months following discharge (n=142; 76.8 percent retention rate, excluding six participants who died). Patients stayed in treatment for an average of 110 days (SD=64.2). The study was approved by the local institutional review board.

Measures
SUD Symptom Count
We used the SCID-I at the baseline and twelve-month follow-up interviews to collect information regarding participants’ SUD symptoms (i.e., DSM-IV diagnostic symptoms for abuse and dependence of alcohol and drugs). This approach is consistent with the DSM-5’s dimensional approach to SUD diagnosis. SUD symptoms are widely known and routinely used by clinicians, which increases interpretability of results. To calculate the total number of SUD symptoms, we added the number of symptoms for alcohol and for drug use.
Interpersonal Styles
At the baseline interview, we used the IIP-C to characterize problematic interpersonal styles (Alden et al., 1990). It is comprised of eight subscales corresponding with the types of interpersonal styles:
1. Domineering (e.g., “I argue with other people too much”)
2. Intrusive (e.g., “I want to be noticed too much”)
3. Overly nurturant (e.g., “I try to please other people too much”)
4. Exploitable (e.g., “I find it difficult to say ‘no’ to other people”)
5. Nonassertive (e.g., “I find it difficult to tell a person to stop bothering me”)
6. Socially avoidant (e.g., “I find it difficult to join in on groups”)
7. Cold (e.g., “I find it difficult to show affection to people”)
8. Vindictive (e.g., “I find it difficult to really care about other people’s problems”)
Each subscale has eight items rated on a five-point Likert scale (values ranged from zero [“Not at all”] to four [“Extremely”]) that were summed to create a score for each subscale. We standardized scores according to norms provided by Horowitz, Alden, Wiggins, and Pincus (2000) and report standard scores on a T-scale metric with a mean of fifty and standard deviation of ten.
Poor Relationship Quality with Peers in Treatment
One month into treatment, we asked participants about the quality of their relationships with other residents in the program. Participants completed an adapted version of the Life Stressors and Social Resources Inventory (LISRES; Blonigen, Timko, Finney, Moos, & Moos, 2011; Moos, Fenn, Billings, & Moos, 1988), designed to measure resources and stressors across several life domains. We used the Stressors subscale to measure poor relationship quality of participants with peers in treatment. Items on the Stressors subscale include, “Are other residents critical or disapproving of you?” and “Do any of the other residents get angry or lose their temper with you?” Participants rated the items on a five-point Likert scale with values ranging from one (never) to five (often).

Analytical Plan
Because the subscales of the IIP-C were highly related to one another, we used principal components analysis (PCA) to reduce redundancy in our analyses. To answer our remaining research questions, we followed the approach to mediational analysis proposed by Hayes (2013). This approach allowed us to test whether interpersonal styles predicted SUD outcomes (direct effect) and whether the relationship quality with peers in treatment mediated this relationship (indirect effect). We tested models for total interpersonal problems (total score of the IIP-C) as well as each factor identified through the PCA. Mediation analyses were conducted using the PROCESS macro for SPSS developed by Andrew Hayes (Hayes, 2012). We controlled for scores on the outcome variable (SUD symptom count) at baseline and length of stay in the treatment program in our analyses.

Results
SUD symptom count decreased significantly from the baseline interview to the twelve-month follow-up (t=12.03; P <.0001). Veterans in treatment reported more interpersonal problems than the normative sample; they had a mean total standardized score of 60.2 on the IIP-C, which ranks in the 84th percentile. Veterans also scored higher on all individual domains measured by the eight subscales of the IIP-C.
Intercorrelations among Study Variables
Notably, the magnitude of the correlation between SUD symptom count at baseline and SUD symptom count twelve months after discharge (r=.31, P<.01) was comparable to the magnitude of the correlation between the IIP total score at baseline and SUD symptom count twelve months after discharge (r=.29, P<.01).
Subscales of the IIP-C were positively associated with each other. IIP-C subscales reflecting high dominance (e.g., domineering, intrusive) and low affiliation (e.g., vindictive, cold, socially avoidant) predicted poor relationship quality with peers one month into treatment as well as a higher SUD symptom count at the twelve-month follow-up. Poor relationship quality with peers one month into treatment also predicted more symptoms of SUDs at the twelve-month follow-up.

Principal Components Analysis (PCA)
As previously described, we conducted a PCA to reduce redundancy in the IIP-C scale scores when examining mediation models. We found three factors, which accounted for 85.8 percent of the variance in the IIP-C scales scores. The nonassertive, exploitable, and overly nurturant subscales loaded onto the first factor, which we named “passive” (Cronbach’s α =0.92). The second factor, titled, “cruel/aloof,” included the vindictive, cold, and socially avoidant subscales (Cronbach’s α=0.92). The domineering and intrusive subscales loaded onto the final factor, which we called “controlling” (Cronbach’s α=0.83).

Testing Poor Relationship Quality with Peers in Treatment as a Mediator between Interpersonal Styles and SUD Symptoms
We examined mediation models testing the extent to which poor relationship quality with peers one month into treatment mediated the relationship between interpersonal styles at intake and SUD symptoms twelve months after discharge. We tested the associations between the IIP-C total score as well as the three factors emerging from the PCA separately. We highlight the results of the overall F test and the percent of variance explained by each model (R2) as well as the direct and indirect effects of the IIP-C score on the outcome.
IIP-C Total Score
The model for the IIP-C total score (n=122) was significant (R2=0.203; F(1,120)=7.459, p<0.000). The direct effect was also significant in that more interpersonal problems predicted a greater number of SUD symptoms at twelve-month follow-up. Additionally, the indirect effect was important: more interpersonal problems at baseline led to more SUD symptoms at twelve-month follow-up via poor relationships with peers in treatment. Therefore, mediation was supported in this model.

Passive Factor
The model for the passive factor was significant too (n=114; R2=0.195, F(4,109)=6.584, p<0.000). The direct effect of the passive factor on SUD symptom count was noteworthy, such that a more passive interpersonal style predicted a greater number of SUD symptoms. However, we did not find evidence of mediation. The passive factor was not associated with poor relationship quality with peers, and the indirect effect of this model was not significant.

Cruel/Aloof Factor
The model for the cruel/aloof factor was significant (n=114; R2=0.157; F(4,109)=5.088, p>0.001). Although the direct effect of scores on the cruel/aloof factor on SUD symptom count at the twelve-month follow-up was not substantial, the indirect effect was. Thus, a cruel/aloof interpersonal style led to more symptoms of SUDs at the twelve-month follow-up, and this relationship was mediated by poor relationships with peers in treatment. Mediation was supported for the cruel/aloof factor.
Controlling Factor
The final model was also significant (n=114; R2=0.176, F(4,109)=5.838, p>0.001). The direct effect of the controlling factor on SUD symptom count was not significant. However, the indirect effect of the controlling factor on SUD symptom count was noteworthy, such that a more controlling interpersonal style led to more SUD symptoms one year after discharge via poor relationships with peers in treatment. Mediation was supported for the controlling factor.

Discussion
To our knowledge, this is the first study to examine the role of interpersonal styles on SUD treatment outcomes among US veterans in residential treatment. We found that veterans in residential treatment reported more total interpersonal problems than the general population by a magnitude of one standard deviation. The most common types of problematic interpersonal styles exhibited by veterans were those associated with low levels of affiliation: domineering, vindictive, cold, and socially avoidant. Moreover, we found that interpersonal styles were associated with long-term SUD outcomes, such that higher levels of interpersonal problems predicted a greater number of SUD symptoms one year after treatment. In previous research, substance use at the time of treatment entry is typically a robust predictor of outcome (Read, Brown, & Kahler, 2004). Our results suggest that interpersonal styles may be an equally good predictor of treatment outcome. Even when controlling for SUD severity at time of entry into the residential treatment program, interpersonal styles play an important role in predicting SUD severity after discharge.
The relationship between interpersonal styles and treatment outcomes was mediated by relationship quality with peers in treatment. These results support prior research demonstrating that social context is an important aspect of SUDs (Galea et al., 2004; Leach & Kranzler, 2013). Previous work has focused primarily on the role of social support networks and peer influences on treatment outcomes in mutual-aid groups (Groh et al., 2008). Our findings extend this literature by demonstrating that interpersonal styles negatively affect the formation of social support networks during residential treatment, and in turn influence outcomes. Residential settings, as opposed to outpatient settings, are an ideal location to examine the associations between social variables and outcomes. Residents in inpatient programs have both positive and negative interactions with one another at many points throughout each day, and peer relationships are a central aspect of treatment. Accordingly, interpersonal styles may have a greater impact in residential settings than in outpatient treatment.
Specific types of interpersonal styles were differentially associated with treatment outcomes. The relationship between both the controlling and cruel/aloof interpersonal styles and SUD outcomes were mediated by poor relationship quality with peers in treatment. The subscales that comprise these factors are characterized by externalizing behaviors. These behaviors may contribute to difficulty forming and maintaining relationships with peers in the treatment setting, as disruptive behaviors may cause conflicts with other residents. For those with controlling and cruel/aloof interpersonal styles, lack of social support may reduce the efficacy of treatment.
Although we did not find evidence for mediation for the passive factor, high scores nevertheless predicted poor SUD outcomes. The passive factor is comprised of subscales—nonassertive, exploitable, and overly nurturant—that are low in dominance and associated with social anxiety (Kachin, Newman, & Pincus, 2001). Residents with a passive interpersonal style therefore may be less disruptive to the milieu and cause fewer explicit disagreements with other residents. In a setting characterized by high rates of conflict, providers may not recognize internalized distress experienced by residents with a passive interpersonal style. These unaddressed problems may lead to poor long-term SUD outcomes.

Limitations
This study had several limitations. First, these data are self-report, and our findings reflect the individuals’ understanding of their own interpersonal styles. Insight into their own relationships may be limited, and peers’ perceptions therefore may be equally important. Moreover, because the majority of participants were men, we could not examine gender differences. Relationships and social context differ between men and women with problematic substance use (Timko, Finney, & Moos, 2005), so it is important for future work to include women. In addition, diagnostic data on other psychiatric disorders (e.g., mood and anxiety disorders) were not collected on participants; thus, we could not examine the role of interpersonal processes on treatment outcomes in the context of comorbid psychiatric conditions.
Our results may not be generalizable to nonveteran populations. Military recruits have lower levels of “agreeableness” (i.e., a personality trait associated with a desire for social harmony) when they join the armed forces (Jackson, Thoemmes, Jonkmann, Lüdtke, & Trautwein, 2012). These already low levels further decrease after military training (Jackson et al., 2012). Low agreeableness would be consistent with vindictive, cold, or socially avoidant types of interpersonal problems. Social support may function differently for populations higher in agreeableness who exhibit different interpersonal styles.

Implications for Treatment and Future Directions for Research
Despite these limitations, our results have several implications for improving treatment. First, providers may wish to routinely assess interpersonal styles of patients in residential SUD treatment. For milieu-based programs, integrating measures of interpersonal styles would help to both tailor treatment to individuals and to anticipate potential disturbances within the milieu setting. For example, those with a passive interpersonal style may benefit from providers increasing their awareness of internalized distress that may otherwise go unnoticed. Prioritizing interpersonal styles may also increase the cost-effectiveness of treatment. Residential milieu-based treatment programs are typically expensive (Kaskutas, Zavala, Parthasarathy, & Witbrodt, 2008), and improving outcomes by focusing on problematic interpersonal styles may reduce readmissions and lead to better quality of life for clients.
Our findings suggest it may be helpful to augment and adapt existing outpatient psychosocial treatments to include a focus on interpersonal styles. For example, network support (NS) treatment (Litt et al., 2016) reduces problematic alcohol use by helping clients shift their social support networks to include sober individuals and exclude substance-using contacts. Litt and colleagues (2016) found that enhancing NS with social skills training, which taught participants how to meet and interact with new acquaintances, assisted in positively changing social support networks. Therefore, including additional material addressing a broader range of social issues, especially problematic interpersonal styles, may further improve efficacy.
Alternatively, clinicians may benefit from adapting empirically supported treatments that already include a focus on interpersonal styles. For example, both dialectical behavior therapy (DBT) and skills training in affective and interpersonal regulation (STAIR) are widely disseminated therapies that treat borderline personality disorder and trauma symptoms, respectively. Both treatments include modules that teach clients to better understand interpersonal problems in their own lives and learn to respond to others in more effective ways. Adapting these therapies to focus on the needs and experiences of people with primary diagnoses of SUDs is an important next step.

Acknowledgements: Dr. Harrison was supported by the National Institute on Drug Abuse of the National Institutes of Health (T32DA007250). Dr. Blonigen was supported by a Career Development Award (CDA-2-008-10S) from VA Clinical Science Research & Development (awarded to Dr. Blonigen). Dr. Timko was supported by a Senior Research Career Scientist Award (RCS-00-001) from VA Health Services Research & Development. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Veterans Health Administration.
About the Authors
Anna J. Harrison, PhD, is a postdoctoral scholar in the drug abuse treatment and services research training program in the Department of Psychiatry at the University of San Francisco, California. Her program of research focuses on SUDs among justice-involved youth and young adults. She is particularly interested in finding ways to expand access to and engagement in substance use treatment among justice-involved populations.
Christine Timko, PhD, is a senior research career scientist at the Department of Veterans Affairs, Health Services Research & Development (HSR&D) Service; and clinical professor (affiliate) at the Department of Psychiatry and Behavioral Sciences at Stanford University School of Medicine. Her research and mentoring focus on quality of care for individuals with substance use and other mental health disorders.
Daniel M. Blonigen, PhD, is a research health science specialist at the HSR&D Center for Innovation to Implementation at the VA Palo Alto Health Care System; a clinical assistant professor (affiliated) in the Department of Psychiatry and Behavioral Sciences at Stanford University School of Medicine; and an adjunct professor at Palo Alto University. His program of research focuses on assessment and engagement in care among individuals with substance use and co-occurring psychiatric disorders, with a focus on populations marked by chronic homelessness and/or involvement in the criminal justice system.
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Editor’s Note: This article was adapted from an article by the same authors previously published in the Journal of Substance Abuse Treatment (JSAT). This article has been adapted as part of Counselor’s memorandum of agreement with JSAT. The following citation provides the original source of the article:
Harrison, A. J., Timko, C., & Blonigen, D. M. (2017). Interpersonal styles, peer relationships, and outcomes in residential substance use treatment. Journal of Substance Abuse Treatment, 81, 17–24.