An Effectiveness Trial of a Selected Dissonance-Based Eating Disorder Prevention Program for Female High School Students: Long-Term Effects.

Eating disorders, which afflict 10% of adolescent girls and young women, are marked by functional impairment, morbidity, mental health service utilization, and increased risk for future health and mental health problems (Johnson, Cohen, Kasen, & Brook, 2002; Lewinsohn, Streigel-Moore, & Seeley, 2000; Stice, Marti, Shaw, & Jaconis, 2009a; Wilson, Becker, & Heffernan, 2003). Thus, a public health priority is to develop effective eating disorder prevention programs. Efficacy trials have produced considerable empirical support for a dissonance-based eating disorder prevention program (Stice, Mazotti, Weibel, & Agras, 2000). In this selective prevention program young women at risk for eating disorders because of body image concerns critique the thin ideal espoused for women in verbal, written, and behavioral exercises. These activities theoretically produce cognitive dissonance that motivates participants to reduce their pursuit of the thin-ideal, producing reductions in body dissatisfaction, unhealthy weight control behaviors, negative affect, and eating disorder symptoms. Efficacy trials show that this prevention program produces greater reductions in eating disorder risk factors (e.g., thin-ideal internalization, body dissatisfaction, self-reported dieting, and negative affect), eating disorder symptoms, functional impairment, and future onset of eating disorders over a 3-year follow-up relative to assessment-only or alternative intervention control conditions (e.g., Stice et al., 2000; Stice, Shaw, Burton, & Wade, 2006; Stice, Marti, Spoor, Presnell, & Shaw, 2008). Efficacy trials evaluate whether preventive interventions produce effects under carefully controlled experimental conditions, in which the facilitators are methodically trained and supervised, the intervention is typically delivered in adequately staffed research clinics, and the participants are often homogenous (Flay, 1986). Efficacy trials conducted by independent labs have also found that dissonance-based eating disorder prevention programs produce greater reductions in risk factors and eating disorder symptoms relative to assessment-only control conditions and alternative interventions (e.g., Becker, Smith, & Ciao, 2005; Mitchell, Mazzeo, Rausch, & Cooke, 2007; Roehrig, Thompson, Brannick, & van den Berg, 2006; Wade, George, & Atkinson, 2009). Impressively, dissonance-based prevention programs have even reduced eating disorder risk factors and symptoms when college students deliver the intervention in dissemination research (Becker, Bull, Schaumberg, Cauble, & Franco, 2008; Becker, Smith, & Ciao, 2006; Parez, Becker, & Ramirez, 2010). Consistent with the intervention theory for the dissonance-based eating disorder prevention program, there is evidence that reductions in thin-ideal internalization mediate the effects of the intervention on change in the outcomes (Seidel, Presnell, & Rosenfield, 2009; Stice, Presnell, Gau, & Shaw, 2007b; Stice, Marti, Rohde, & Shaw, in press). In support of the notion that dissonance induction contributes to the effects of this intervention, participants assigned to high-dissonance versions of this program show significantly greater reductions in eating disorder symptoms than those assigned to low-dissonance versions of this program (Green, Scott, Divankova, Gasser, & Pederson, 2005; McMillan, Stice, & Rohde, 2011), though these trials clearly imply that intervention content and non-specific factors (e.g., perceived group support) also contribute to intervention effects. Given the empirical support for this eating disorder prevention program from efficacy trials conducted by independent labs, we initiated a large effectiveness trial of this intervention. Effectiveness trials evaluate whether interventions produce effects when delivered by endogenous providers (e.g., school counselors) who are not closely supervised under real world conditions in natural settings with heterogeneous populations (Flay, 1986). It is vital to conduct effectiveness trials because a prevention program that produces effects in highly controlled efficacy trials may be ineffective when delivered under real world conditions by endogenous clinicians. Effectiveness trials can also provide information concerning the degree of training and supervision necessary to achieve intervention effects and have the potential to reveal problems that must be resolved before the prevention program can be successfully disseminated (e.g., effectiveness trials might reveal that typical high schools do not have clinical staff with experience delivering group-based interventions). The present trial utilized several design elements consistent with effectiveness research (Roy-Byrne et al., 2003). First, we implemented this prevention program in three entire school districts rather than a subset of schools in a district. Second, high school nurses and counselors, rather than research staff, recruited participants and delivered the intervention within the school environment. Third, we standardized and streamlined facilitator training; endogenous providers completed a 4-hour training session and received limited supervision to mimic real-world conditions. We also used a new 4-session version of the intervention (versus the original 3-session version) that made it easier for endogenous providers to cover the same intervention exercises. Fourth, we minimized exclusion criteria; only adolescent females who met criteria for an eating disorder were excluded. Fifth, we used a minimal intervention educational brochure control condition because this was the only extant resource for students in local high schools, making this an ecologically valid control condition. An earlier report from the present effectiveness trial found that female high school students who were randomized to the dissonance intervention showed significantly greater decreases in thin-ideal internalization, body dissatisfaction, self-reported dieting, and eating disorder symptoms from pretest to posttest than educational brochure controls, with the effects for body dissatisfaction, dieting, and eating disorder symptoms persisting through 1-year follow-up (Stice, Rohde, Gau, & Shaw, 2009b). This is noteworthy because almost no eating disorder prevention programs have produced intervention effects for eating disorder symptoms through 1-year follow-up (Stice, Shaw, & Marti, 2007c). The first aim of the current report is to test whether intervention effects from this effectiveness trial persist through 2- and 3-year follow-up. We hypothesized that participants randomized to the dissonance intervention would show greater reductions in risk factors (thin-ideal internalization, body dissatisfaction, self-reported dieting, negative affect), eating disorder symptoms, and risk for onset of threshold and subthreshold anorexia nervosa, bulimia nervosa, and binge eating disorder relative to educational brochure controls. The second aim is to investigate the effects of this prevention program on other ecologically meaningful outcomes, including risk for overweight or obesity onset, psychosocial functioning, and mental health care utilization. The third aim is to benchmark the magnitude of the effects form this effectiveness trial against those observed in our large efficacy trial (Stice et al., 2008).