Effect of dopamine D₃ receptor antagonism on approach responses to food cues in overweight and obese individuals.

The aim of the study was to examine the effect of manipulating the brain dopamine system, using a D₃ receptor antagonist, on approach responses to food cues in overweight and obese individuals. Twenty-six healthy overweight and obese participants were randomly assigned to receive either a single dose of dopamine D₃ receptor antagonist, GSK598809 (175 mg), or placebo in the first assessment session and vice versa in the second session. Using a stimulus-response compatibility task, approach bias was indexed by response latency to move an image of a manikin towards, versus away from, pictures of food, relative to nonfood stimuli. Data from the first session (which were unaffected by repeated testing) indicated that approach bias scores were significantly reduced in overweight and obese participants who received GSK598809, compared with those who received placebo. Data from the second session were confounded by an effect of treatment order and, consequently, were uninformative for the hypotheses. Between-participant comparison of drug versus placebo conditions indicated that GSK598809 attenuated approach bias to food cues, which is consistent with the reduction in their motivational attractiveness. The findings, albeit preliminary, are in agreement with the view that D₃ receptor antagonists may prove useful as therapeutic agents for reducing appetitive responses to food cues in obesity.