The United States has a serious weight problem. Two-thirds of our adults are overweight or obese. The prevalence of overweight among our children has nearly tripled since 1970.

The consequences for the Nation's health and economy are grave. Obesity has been shown to decrease overall life expectancy and to increase the risk for cardiovascular disease, type 2 diabetes, and other chronic conditions. Annually, it costs an estimated $117 billion or more in lost productivity and future earnings. To identify new strategies for prevention and treatment, the National Institutes of Health (NIH) has established an Agency-wide obesity task force and research plan (see obesityresearch.nih.gov).

NIDA's assignment on the 25-Institute task force represents a natural extension of the Institute's research agenda. Addiction and compulsive eating both involve impaired impulse control and distorted valuation of the rewards to be derived from a certain behavior—i.e., drug-taking or eating. The two conditions have roots in some of the same brain areas and circuits, including the hypothalamus, prefrontal cortex, and limbic system. The knowledge NIDA-funded scientists have developed of how those areas function normally and in the context of drug abuse undoubtedly will have great application to understanding the other compulsive behavior.

In this issue, we report an exemplary illustration of the neurobiological overlap between addiction and eating disorders: The hormone orexin appears to foster cravings for both food and drugs (see "Neuropeptide Promotes Drug-Seeking and Craving in Rats"). Several other NIDA-supported studies are investigating compounds found to be effective in suppressing appetite and food intake. Some of the most promising produce their effects by blocking the brain's cannabinoid receptors, which are targeted by THC, the active ingredient in marijuana (cannabis), a drug with marked effects on appetite. Researchers hope to translate this knowledge into medications for weight control, drug abuse treatment, or both.

EFFORTS BY OTHER INSTITUTES IN THE COLLABORATION INCLUDE:

• A program, led by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), to foster a multidisciplinary approach to clinical obesity research in areas such as metabolism, endocrinology, nutrition, cardiovascular biology, digestive diseases, genetics, and behavioral sciences; and
• Projects to combat pediatric obesity in primary care, day care, schools, and other community settings by exploring effective methods to curb weight gain, including changes in food and lifestyle choices.

We hope that further research into the many factors that contribute to obesity—including neural systems that modulate appetite and eating behavior—will lead to the development of new therapies for obesity as well as addiction.

Volume 21, Number 4 (October 2007)