Introduction

Lifetime prevalence rates of binge-eating disorder (BED) are three times higher than other eating disorders [1]. While BED is typically diagnosed during the early-to-mid-20s, the propensity to use food as a coping mechanism for stress management often begins in adolescence and progresses into more disordered eating behaviors as environmental and economic stressors increase in the early adulthood [2]. Research has found loss of control eating behaviors during adolescence, a central component of binge-eating behaviors, to be related to increased risk for developing full syndrome eating disorders later in life [3]. Emotional overeating, or eating in excess to soothe negative emotions, can be conceptualized as subthreshold binge-eating behavior, and may occur prior to onset of full-criteria BED. Due to the more common presentation of subthreshold binge-eating behaviors in adolescence, intervention efforts for youth with subthreshold presentations are needed and may serve to alter the progression of BED into adulthood.

Dialectical behavior therapy (DBT) has emerged as an efficacious treatment for BED in adults, specifically when targeting emotionally driven binge-eating behaviors [4]. Furthermore, DBT has been found to lead to more long-term sustained improvements in binge-eating behaviors among adults, as compared to other therapeutic treatment approaches [5]. While few studies have explored the efficacy of DBT for adolescent-eating disorders, preliminary findings are promising [6]. DBT has been found to be a highly effective treatment for other emotionally driven problematic behaviors among adolescents, such as self-harm [7]; however, DBT for adolescents traditionally includes numerous therapeutic aspects to ensure fidelity to this model. In the context of subthreshold presentations, such as emotional overeating, the use of more targeted, streamlined skills interventions may be indicated. Assessment of adapted designs to target the early BED behaviors has been identified as a crucial need in the field [5]. While adapted DBT skills interventions for overeating behaviors have shown promising results among adults [8], the impact of a less intensive, condensed DBT skills intervention on adolescent binge-eating behaviors and subthreshold presentations (e.g., emotional overeating) is unknown. Accordingly, this pilot study examined the feasibility of implementing a condensed DBT skills-based group intervention for adolescents exhibiting emotional overeating behaviors, with skills taught aimed at decreasing emotional overeating practices [9].

Methods

Participants

Participants were adolescents (14–18 years) receiving outpatient medical care at a pediatric hospital in Memphis, Tennessee. Inclusion criteria included endorsement of any current or prior emotional overeating behaviors. Exclusion criteria included lack of caregiver consent or diagnosis of intellectual disability, due to decreased autonomy in food choices.

Procedure

Screening and recruitment

Following approval from the Institutional Review Board at the University of Tennessee Health Science Center, screening and recruitment commenced. Patients 14–18 years were screened for endorsement of emotional overeating behaviors in hospital-based outpatient clinics over a period of 3 months. Upon check-in at clinic, youth received a form with items corresponding to DSM-5 criteria for BED in a yes/no format (available in the Supplemental Materials). Any patients endorsing at least one of these behaviors were contacted by study personnel to assess their interest in participating in an intervention.

Intervention

To increase accessibility for participants and maximize recruitment efforts, five groups were offered at different days and times (including evenings and weekends) and start dates were staggered. On average, five group members were assigned to each group, with a baseline range of 4–6 participants per group. The group intervention occurred over 10 sessions, with baseline assessments at session 1, skills-based groups during sessions 2–9, and post-intervention assessments at session 10. Skills-based groups were 1 h in length, and facilitated by graduate student clinicians and a clinical psychologist. All facilitators and co-facilitators received a multi-day training in the intervention protocol and the specific DBT skills implemented prior to beginning groups, led by a clinical psychologist (senior author) and an advanced clinical psychology graduate student (first author), both with extensive DBT skills experience and training. Group facilitators completed fidelity checklists each session to ensure consistency across groups. Follow-up assessments occurred 3-month post-intervention. Youth assessment measures took approximately 1 h to complete, while caregiver assessments took approximately 30 min. Youth received a $10 gift card to a local vendor each time that they completed assessments.

Session 1 served as an individual orientation and assessment session with adolescents and caregivers. Each skills-based group (i.e., sessions 2–9) began with a mindfulness activity and introduced a core DBT skill (details of sessions available in table form in the Supplemental Materials; see reference [9] for a more detailed description). Didactic and experiential activities were culturally and developmentally tailored to make content relevant for the majority racial/ethnic minority adolescent participants. Homework and progressive diary cards were assigned to reinforce incorporation of new skills outside of session. Participants received a $5 gift card each week which they completed their homework and diary card. Weekly assignments required participants to practice skills at home and teach the skills to a family member to promote the generalization of skills in alternate milieus. Session 10 included a review of skills learned over the course of the intervention and caregivers were invited to engage in a meal celebrating completion of the intervention, practicing mindful eating. All participants who completed the intervention were entered into a drawing for a $150 gift card.

Measures

Sociodemographic questions pertaining to participants’ age, gender, race, ethnicity, and socioeconomic status were collected. Participants’ weight and height were measured to calculate body mass index (BMI) using a Scale-Tronix 5002 bariatric stand-on scale and ShorrBoard wall-mounted stadiometer, respectively. BMI was calculated (kg/m2) and transformed to z scores, which were standardized by age and sex.

Objective binge episodes (OBEs) were assessed using the Eating Disorder Examination Questionnaire (EDE-Q), a widely used 28-item measure of disordered eating behaviors [10], which provides a frequency score of OBEs. Caregiver report of youth OBEs was also assessed using the EDE-Q. Emotional overeating behaviors were assessed using the Emotional Eating Scale for Children and Adolescents (EES-C) [11], a 26-item, self-report measure of desire to eat in response to specific emotions. Higher scores indicated greater engagement in these behaviors. Parental report of youth emotional overeating behaviors was also assessed with the EES-C. Finally, participants completed a brief 8-item questionnaire assessing their acceptability of the intervention using Yes, No, and Don’t Know responses (e.g., ‘I found this intervention helpful’; available in the Supplemental Materials).

Results

Of the 30 participants who completed baseline assessments, 15 completed the intervention, resulting in 50% attrition. No significant differences were found between Intervention Completers and Non-Completers on any reported demographics (see Table 1 for sample characteristics). Of the 15 participants who completed post-intervention assessments, 11 were retained at 3-month follow-up, yielding 26.7% attrition. The last observation carried forward (LOCF) method of intent to treat analysis has been identified to result in biased findings when the missing data are not completely random, and when the missing data do not have the exact same distribution as the data being used for imputation [12]. Given the small sample size of this feasibility pilot trial, and the fact that missing data of those lost to follow-up were not random and thus commensurate distribution cannot be assumed, the LOCF method was determined to be particularly vulnerable to biasing results. Furthermore, as a pilot study assessing feasibility of the intervention, recommendation to only report accurate descriptives of the data obtained, rather than computing any inferential statistics with p values for hypothesis testing, was followed [13]. Thus, only descriptive statistical values at each time point are provided. Descriptive statistics are provided for the full intervention sample (n = 15) for baseline to post-intervention changes. In addition, descriptives are also provided for those who completed follow-up assessments at 3 months (n = 11). This approach was selected to present as accurate a representation of the data as possible.

Table 1 Sample characteristics and demographics
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Among all Intervention Completers, those meeting criteria for BED decreased from six (40%) at baseline to three (20%) at post-intervention. Among those who completed follow-up, only one (9.1%) met criteria at the 3-month follow-up. Based on mean values, reductions in both youth report of OBEs and emotional overeating and caregiver report of youth OBEs and emotional overeating were observed from baseline to post-intervention among all Intervention Completers. Figure 1 illustrates the reports of OBEs and emotional overeating at baseline (n = 15), post-intervention (n = 15), and 3-month follow-up (n = 11). Based on the responses to the intervention acceptability questions, 86.7% (n = 13) of participants who completed the intervention reported that they would be willing to participate again, while 93.3% (n = 14) reported that they would suggest the intervention to someone else with emotional overeating. All participants (100%, n = 15) reported using the skills to resist the urge to emotionally overeat, felt confident in their ability to use skills in the future, and found the intervention helpful.

Fig. 1
figure 1

Means and standard errors of objective binge episodes and emotional overeating based on youth and caregiver report

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Discussion

While condensed DBT skills interventions for BED and related symptomatology have shown promise with adults [8], research with adolescents is in its nascency. Results from this uncontrolled pilot trial support preliminary evidence of the feasibility of a condensed DBT skills intervention to decrease emotional overeating. Changes in mean values from baseline to post-intervention and baseline to 3-month follow-up demonstrated improvement in emotional overeating behaviors based on youth and caregiver report. While such evidence is an important metric of feasibility of a novel intervention, acceptability to participants is critical, as well. Measures of acceptability suggest that participants who completed the intervention found it highly acceptable. When determining acceptability, however, it is also important to consider that 50% of participants discontinued from initial baseline to post-intervention, despite use of weekly gift card incentives. This attrition rate should be considered within the context of the high attrition rates of similar studies evaluating adapted DBT interventions, in which most drop-out rates occur at the beginning of treatment [8]. This is consistent with the present intervention, in which attrition occurred predominantly in the first few sessions. The high attrition rates of pediatric overeating and weight management interventions should also be taken into consideration, which demonstrate average attrition rates ranging upwards of 73% [14]. It is important to note that this was not specifically a weight management study, as engagement in emotional overeating is not restricted to those with elevated weight. Furthermore, the present intervention did not restrict inclusion to those with overweight or obesity, a notable strength of this study. Given that the majority of participants for the present were recruited from a pediatric obesity clinic (77%), however, the high attrition rates in this field of intervention [14] should be considered when evaluating the feasibility of the intervention.

Though yielding important findings, the present study had a number of limitations. Difficulties with retention were anticipated, and the a priori analytic plan for a feasibility pilot study deemed it appropriate to compare descriptive statistics regardless of the number completing the intervention [13]; however, the small sample size and high drop-out rate are notable. Thus, replication of the promising findings is needed with a larger sample. The use of an uncontrolled pilot study design is another limitation. Though an important first step in intervention development, this design limits the conclusions that can be made regarding intervention efficacy due to the lack of inferential statistics appropriate for use with feasibility studies [13]. Despite promising results, efficacy of the intervention cannot be confidently established due to the lack of a control group. As such, implementation of a randomized-controlled trial in future research is needed to establish efficacy. Furthermore, generalizability of findings is limited by sample homogeneity. Though recruitment was not limited based on identified racial/ethnic background, Black youth represented the majority of the treatment population where recruitment occurred, resulting in a largely homogenous sample. Future iterations should explore intervention implementation with a more racially/ethnically diverse sample. Finally, the use of gift card incentives limits the generalizability to standardized clinical settings. After attending to these next steps, assessment of acceptability by providers in pediatric health care settings, in addition to acceptability by participants, will be important.

This pilot intervention demonstrates potential to prevent the future development of BED by decreasing emotional overeating. Given the association between subthreshold binge-eating behaviors in youth and full-criteria BED in adulthood [3, 15], intervening when problematic eating behaviors are subthreshold may ameliorate mental and physical health sequelae, thereby reducing individual and public health costs. Moreover, this study’s support for the implementation of a condensed DBT skills intervention has the potential to increase scalability, facilitating dissemination to a larger number of youth. These findings suggest that targeted training of DBT skills may be a feasible and appropriate way to treat subthreshold pediatric presentations and decrease risk of development of more severe presentations that require more intensive modalities [4, 5].