Motivational Interviewing for Weight Loss

• Physiological outcomes [ Time Frame: Change over time from Baseline to 6 months (measured monthly) with a 12 months reassessment ] [ Designated as safety issue: No ]

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

  The Weight Loss Behavior Scale (WLBS; Smith, Williamson, Womble, Johnson, & Burke, 2000) is a 35-item questionnaire designed to be a brief measure of changes in eating and exercise habits over the course of weight loss treatment.

• Psychological well-being [ Time Frame: Change over time from Baseline to 6 months (measured monthly) with a 12 months reassessment ] [ Designated as safety issue: No ]
  Rosenberg Self-Esteem scale, Pediatric Quality of Life Inventory (PEDS QL), Child depression inventory, Adolescent coping (A-COPE)

The investigators will aim to determine the effect of motivational interviewing on self efficacy, health behaviors, and health outcomes in overweight adolescents.

One empirically supported intervention with a large evidentiary 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.

• Behavioral: Motivational Interviewing
  Motivational interviewing (MI) can thus 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.
• Behavioral: Individual Standard Therapy
  Six sessions of individual supportive therapy (administrator will use a script as a guideline for their intervention) in place of Motivational Interviewing (MI); sessions will be matched for session frequency and duration. This student will not be trained in motivational interviewing. They will be instructed to strictly focus on weekly exercise and food goals for the participant and will follow a semi-structured interview to control type and quality of therapy provided. These sessions will also be audio taped and reviewed by an MI expert to verify that MI techniques have not been used.

• Experimental: Motivational Interviewing Group
  Motivational Interviewing (MI) treatment group, a clinical psychology doctoral student trained in Motivational Interviewing will administer approximately six individual motivational interviewing treatment sessions approximately 30 minutes in length.
  Intervention: Behavioral: Motivational Interviewing
• Active Comparator: Control Group
  The control group will receive standard supportive therapy.
  Intervention: Behavioral: Individual Standard Therapy

Inclusion Criteria:

• Obese youth (with Body Mass Index (BMI) >95th %ile for age and gender (as classified by the Center for Disease Control))
• age 10-18 years, attending a local obesity clinic ("Healthy Weights" clinic) will be eligible to participate.

Time of entry into the weight-loss program will also be controlled for; however, both new and current participants will have the option to participate in the study.

Exclusion Criteria:

• taking medication whose side effects may influence weight gain or weight loss
• do not speak English
• demonstrate a developmental delay
• report being pregnant and/or report having an eating disorder