This study found that the central therapeutic techniques of a manualized, empirically supported family-based therapy for adolescent drug abuse and related behavior problems predicted long-term outcomes for both adolescent behavioral symptoms and family process characteristics. Greater use of family-focused techniques during treatment was related to decrease in adolescent internalizing symptoms at 6 months after treatment and increase in family cohesion at 1 year. Family focus also predicted reduced externalizing symptoms and family conflict at 6 months, but only when adolescent focus was high. Greater use of adolescent-focused techniques was related to increase in family cohesion and decrease in family conflict at 1 year after therapy. All significant effect sizes were in the medium or large range, indicating that reported findings are relatively robust.
As hypothesized, family-focused techniques that are traditional staples of family therapy—articulating core relational themes with parents and teens, enhancing family communication and attachment, shaping family interactions (i.e., enactment), and so forth (see G. S. Diamond & Liddle, 1996
)—predicted long-term improvement in adolescent symptoms and family functioning. These results extend the findings from Hogue et al. (2004)
, which reported a relation between MDFT family techniques and internalizing symptoms at treatment discharge. Also, these process–outcome findings linking family techniques to improved family cohesion complement family therapy outcome studies that report clinical gains in family functioning as well as youth outcomes.
An important finding was the fact that adolescent-centered interventions featured within a family-based treatment model uniquely predicted improvements in some client outcomes and moderated the impact of family interventions on others. A hallmark of the MDFT model is the emphasis placed on working directly with the individual teen in conjunction with individual work with the parent, the family as a unit, and extrafamilial influences (Liddle, Rodriguez, Dakof, Kanzki, & Marvel, 2005
). Thus, in addition to meeting conjointly with family members, MDFT therapists meet alone with adolescents on a regular basis, work to establish and maintain a therapist–adolescent alliance, focus on drug use and alternatives to same, build individual social skills, and address other developmental tasks as needed. Within-group analyses across therapy phases revealed that clients in this study received a consistent dose of adolescent techniques on a par with or even greater than family techniques. Moreover, for some outcomes family focus had potent effects only when adolescent focus was strong as well. Taken together, study results indicate that therapists were maximally effective across several domains of functioning when blending a high-dose mix of both family and adolescent techniques, per MDFT protocol specifications.
The clinical impact of both family and adolescent focus in this sample not only confirms a key MDFT intervention principle (need for a variety of individual and systemic foci) but also supports continued development of integrative approaches to adolescent drug abuse that target the individual, family, and larger ecosystem in a coordinated manner (e.g., Latimer, Winters, D’Zurilla, & Nichols, 2003
). Although we found that neither adolescent nor family techniques as measured in this study predicted reductions in drug use, main outcomes from the randomized trial show that MDFT significantly reduced substance use up to 1 year following treatment. This is hard evidence that the MDFT therapist interventions measured by the TBRS instrument did not fully capture all curative aspects of the treatment model. Also, adolescent interventions—therapeutic focus on the adolescent’s antisocial and prosocial activities, peer relations, and personal agenda in therapy—were primarily associated with gains in family relationship outcomes: cohesion and conflict. There are at least two plausible explanations for this connection between adolescent focus and family change. A concurrent explanation holds that promoting prosocial behavior and community citizenship in high-risk adolescents has direct spillover effects into family citizenship domains. A sequential explanation holds that early improvement in adolescent behavior outside the family has later salutary effects on family relations by means of positive family attributions and reduced family stress. Whatever the case, family therapists have long argued that therapeutic focus on broad-based adolescent development produces tangible payoffs in family harmony down the road. To this end, a few studies (e.g., Huey, Henggeler, Brondino, & Pickrel, 2000
) have empirically linked change in adolescent functioning to change in family functioning during family therapy.
A major limitation of the current study is its exclusive focus on the technical aspects of treatment. Nontechnical process components, such as therapeutic alliance, may be equally or more responsible for good outcomes (Horvath & Symonds, 1991
) and may interact with treatment techniques in complex ways (Feeley, DeRubeis, & Gelfand, 1999
). Likewise, this study measured only the extensiveness, not the quality, of therapist interventions. The study measured randomly selected sessions only—between one and three per case—providing only a snapshot of the full course of treatment for any given client. Also, the study used an adherence process measure that examined therapist behavior only and thus did not capture the dynamic, bidirectional process of therapist–client interactions that is at the heart of theories of change in family therapy (Sexton et al., 2004
). This study did not address the issue of the causal relation between changes in family functioning and changes in individual functioning. To disentangle questions about mechanisms of treatment effect, new measurement designs are required that assess processes and outcomes repeatedly over the course of treatment and beyond (Kazdin & Nock, 2003
). In addition, only adolescent-report data were available for measuring family functioning, which is a significant deficit in the measurement of family-level phenomena. Finally, with regard to study generalizability, it is important to note that study participants were a hard-to-engage, hard-to-treat sample of inner-city, juvenile-justice-involved, primarily male, primarily ethnic minority adolescents and their families.
The process–outcome correlations found in this study do not imply that, when it comes to specific treatment techniques, “more is better” in a linear dose–response fashion (Stiles & Shapiro, 1994
). Results indicate only that relatively extensive use of these techniques was associated with relatively large changes in key outcomes for this sample. These findings provide empirical validation for the salience of commonly used family therapy techniques that are practiced to some degree by family therapists of almost every persuasion. Results also endorse the potential utility of adolescent interventions in family therapies other than MDFT, especially treatments for adolescents whose developmental problems include substance abuse and related behavioral symptoms.