Alcoholism is a complex disorder with contributions from both genetic factors and environmental factors, such as stress. In the May 3 Science, Sillaber et al. report the use of a genetic model to investigate stress-induced alcohol drinking in mice (Science 2002, 296:931-933). They studied mice lacking the Crhr1 gene, encoding the receptor for corticotropin-releasing hormone (CRH), which has been implicated in stress-induced psychiatric disorders including alcoholism. Mutant mice consumed larger amounts of alcohol than control animals following repeated stress periods (either social defeat stress or repeated swimming). The increase began around three weeks post-stress and continued for up to six months. Sillaber et al. performed protein profiling for glutamate receptors and found a specific upregulation of the NR2B subunit of the NMDA receptor in the Crhr1-mutants. The authors propose that the genes encoding CRH1 receptor or NR2B may constitute a genetic risk factor for alcoholism.