Elevated cannabinoid 1 receptor mRNA is linked to eating disorder related behavior and attitudes in females with eating disorders

Summary Objective The endocannabinoid system is involved in the regulation of appetite, food intake and energy balance. Methods To study possible differences in CB1 and CB2 mRNA expression in eating disorders, 20 patients with anorexia nervosa (AN), 23 with bulimia nervosa (BN) and 26 healthy women were enrolled into the trial (Homocysteine and Eating Disorders, HEaD). Results We found significantly higher levels of CB1 receptor mRNA in the blood of patients with AN (ΔCT: −3.9 (1.0); KW: 11.31; P = 0.003) and BN (ΔCT: −3.7 (1.7)) when compared to controls (ΔCT: −4.6 (0.6); Dunn's test AN vs. Controls: P < 0.05; BN vs. Controls: P < 0.001) measured by quantitative real-time PCR. No differences were found regarding the expression of CB2 receptor mRNA. Higher CB1 receptor expression was associated with lower scores in several eating disorder inventory-2 (EDI-2) subscales including perfectionism, impulse regulation and drive for thinness. Conclusion Our finding of elevated CB1 -receptor expression in AN and BN adds further evidence to the hypothesis of impaired endocannabinoid signaling in eating disorders.