Motivational Interviewing for Weight Loss

Motivational Interviewing as an Intervention to Increase Adolescent Self-Efficacy and Promote Weight Loss

The investigators studied the effect of motivational interviewing (MI) on self-efficacy, health behaviors, and health outcomes in overweight children and adolescents (ages ranging from 10 to 18 years).

One empirically supported intervention with a large evidence base for improving adult outcomes in behavioral health-related disorders is Motivational Interviewing (MI). MI is strongly rooted in the client-centered therapy of Rogers (1951). Its relational stance emphasizes the importance of understanding the client's internal frame of reference and displaying unconditional positive regard for the client. Motivational interviewing can thus be defined as a client-centered, directive method of therapy for enhancing intrinsic motivation to change by exploring and resolving ambivalence. MI manifests through specific strategies, such as reflective listening, summarization, shared decision making, and agenda setting. Adolescent participants exposed to motivational interviewing in conjunction with usual care (diet and exercise program) are expected to endorse greater self-efficacy, report increased engagement in healthy behaviors, demonstrate a decrease in body weight and report improved psychological outcomes. While motivational interviewing has been shown to increase adults' motivation to make healthy behavior changes, few adolescent studies have demonstrated this effect.

For the Motivational Interviewing (MI) treatment group, a clinical psychology doctoral student trained in Motivational Interviewing administered six individual motivational interviewing treatment sessions, each 30 minutes in length.

The comparison group received six social skills training sessions instead of Motivational Interviewing (MI).

Motivational interviewing (MI) can be defined as a client-centered, directive method of therapy for enhancing intrinsic motivation to change by exploring and resolving ambivalence (Miller and Rollnick, 2002). MI manifests through specific strategies, such as reflective listening, summarization, shared decision making, and agenda setting.

Within the social skills training framework, advice is given to clients and sessions are focused on assigning goals for clients to work towards without specific regard for their readiness to change. The intervention is aimed at finding appropriate ways to navigate typical social situations (e.g., how to negotiate with parents).

A self-efficacy instrument, the Weight Efficacy Life-style Questionnaire (WEL; Clark, Abrams, Niaura, Eaton, & Rossi, 1991) was used to measure participants' beliefs about and confidence in their own ability to make a behavior change, specifically their ability to lose weight. The questionnaire yields a total score, with higher scores indicating higher levels of health-related self-efficacy, as well as 5 situational sub-scores (negative emotions, availability, social pressure, physical discomfort, and positive activities). Individuals rate statements on a 10-point scale ranging from 0 (not confident) to 9 (very confident). The WEL is made up of 20 items (4 items per sub-scale) which are summed to obtain a total score, with the lowest total score possible being 0 and the highest 180. Only the total WEL score was used in the study's analyses. The difference in self-efficacy (WEL) change between treatment and control groups from baseline to a 6 month follow-up was examined.

A second self-efficacy scale, the Child Dietary Self-Efficacy Scale (CDSS; Parcel et al., 1995) was used to measure participants' confidence in their ability to choose lower fat, lower sodium foods. The questionnaire is made up of 20 likert items with 3 response options, including "not sure", "a little sure", and "very sure". Each item asks the participant to indicate how sure he/she is that they would make a healthy choice, for example, "How sure are you that you could eat cereal instead of a donut?" Individual items are scored -1, 0, or 1 and subsequently summed for a total score, with the lowest possible score a -20 and the highest a 20, whereby higher scores signify higher dietary self efficacy.

The study used a Body Mass Index (BMI) percentile for age as the main indicator of weight-loss. Height and weight was measured by the pediatrician at the treatment site and BMI as well as BMI percentile for age was determined with the use of an age appropriate growth curve chart.

Measurements of waist circumference, an indirect measure of central adiposity (or fatness), were also obtained.

Rosenberg Self-Esteem scale, Pediatric Quality of Life Inventory (PEDS QL), Child depression inventory, Adolescent coping (A-COPE)

Inclusion Criteria: Obese youth (with Body Mass Index (BMI) ≥ to 85th percentile for age and gender (as classified by the Center for Disease Control)) ages 10-18 years attending a local obesity clinic ("Healthy Weights" clinic) Time of entry into the weight-loss program was controlled for; however, both new and current participants had the option to participate in the study. Exclusion Criteria: taking medication whose side effects may influence weight gain or weight loss did not speak English demonstrated a developmental delay reported being pregnant and/or reported having an eating disorder