Association between Obesity and Illicit Drug Use in Young Adults

INTRODUCTION: Studies have shown that drugs and food activate common brain reward systems. It has been hypothesized that overeating/obesity may be protective against drug addiction. However, there are only two population-based studies examining this association. Only one of these focused specifically on young adults and none have examined whether this association is moderated by gender. This study's purpose is to examine whether there is an association between obesity and drug use and whether this association varies by gender.

METHODS: Data from the third wave of the National Longitudinal Study of Adolescent Health were analyzed. Participants were 4,882 young adults (mean age = 21.8). Past year use rates of illicit drugs, marijuana, and hard drugs were compared among normal weight (BMI 18.5-24.9 kg/m²), overweight (BMI 25-29.9 kg/m²) and obese (BMI≥30 kg/m²) participants.

RESULTS: Compared to normal weight participants, overweight and obese participants reported significantly lower rates of illicit drug use, marijuana use and hard drug use. Analyses conducted separately by gender showed that overweight and obese males had significantly less odds of engaging in any illicit drug use (aOR=.70 and .61, respectively), marijuana use (aOR=.71 and .62, respectively) and hard drug use (aOR=.55 and .60, respectively) than normal weight males, after controlling for potential confounders.

CONCLUSIONS: The present findings suggest that BMI is inversely associated with any illicit drug use, marijuana use and hard drug use in males, but not for females. The results thus do not uniformly support the hypothesis that obesity may be protective against drug addiction.