Brain, Obesity, Dopamine and You Study

Summary

Central dopamine is thought to play a significant role in obesity. In support of this idea, animal studies and one human positron emission tomography (PET) study have found reduced postsynaptic D2-like receptor availability in the striatum in obesity, with lower D2 receptor availability associated with higher weight. In addition, reward sensitivity and hedonic responses, known to be related to dopamine function, have also been implicated in obesity and obesity-related eating behavior. These reports have led to the concept that dopaminergic abnormalities (e.g. reduced D2-like receptors) influence reward sensitivity, leading to altered eating behaviors and eventually obesity. However, there are several critical limitations of the human D2 receptor studies that limit the strength of their conclusions and thus the interpretations and speculations embedded in literature that relies on this work. First, estimates of D2-like receptors in humans have been confounded by potential differences in endogenous dopamine release since the PET ligand (raclopride) used is known to be displaceable from receptors by endogenous dopamine. Second, failure to rigorously screen obese individuals for diabetes confounds conclusions, since diabetes has been independently associated with dopaminergic abnormalities such as reduced D2-like receptors and muted dopamine release in diabetic rats. Finally, no human studies have addressed whether reduced D2-like receptor levels are a risk factor for obesity, a consequence of engaging in obesity-related behaviors or being obese or all of the above.

Conditions

• Obesity

Interventions

DIETARY_SUPPLEMENT

meal replacements, psychotherapy, dietary education

After the screening and scan days are completed, obese subjects will begin a lifestyle intervention program that includes dietary (low-calorie diet) and behavioral education topics. Treatment will be provided in individual weekly sessions. Each hour-long session will be led by a behavioral counselor or registered dietitian in the Weight Management Center at Washington University. The behavioral program will use cognitive-behavioral techniques to foster adherence to diet prescriptions and to build a supportive environment for the participant. The program will emphasize strategies of self-monitoring and goal-setting, and will include problem-solving, overcoming high-risk situations for unhealthy eating, relapse prevention, and strategies for long-term weight maintenance. Handouts will be provided for study subjects to allow them to record the setting and reaching of dietary goals, as well as summarize the key points of the educational content.

Sponsors & Collaborators

• National Institutes of Health (NIH)

  collaborator NIH

• Washington University School of Medicine

  lead OTHER

Principal Investigators

• Tamara Hershey, Ph.D. · Washington University School of Medicine

Study Design

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

40 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2010-07-31

Primary Completion

2015-06-30

Completion

2016-10-31

Countries

• United States

Study Locations