Anorexia nervosa and the appetite-suppressing “club drug” ecstasy (3,4-methylenedioxymethamphetamine) activate some of the same brain pathways, according to research in mice by French scientists (Jean A. Proc Natl Acad Sci U S A. 2007;104:16335-16340).
The nucleus accumbens (one of the brain's reward centers) contains high concentrations of 5-HT4 receptors, a subset of receptors for serotonin. The researchers found that stimulating 5-HT4 receptors reduced the animals' drive to eat and increased activity of a gene that encodes a satiety peptide that is known to be stimulated in response to cocaine and amphetamines. In contrast, blocking serotonin 5-HT4 receptors increased the animals' food intake.
Stephenson J. Anorexia Nervosa Clue. JAMA. 2007;298(19):2254. doi:10.1001/jama.298.19.2254-b