Schizophrenia and smoking: A common etiology?

An association between schizophrenia and smoking has been observed (de Leon, et al., 1995), however, the possibility of a common genetic etiology has not yet been explored. Cloninger et al. (1998) used genetic data from the NIMH Genetics Initiative for Schizophrenia to examine the schizophrenia/smoking relationship, and found allelic heterogeneity between the African American and European Americans in this sample. In the present work, analyses account for these differences while looking at each ethnic group separately and together. Smoking was defined in terms of packs per year, and was weighted by age. This trait is modeled in full siblings as a function of IBD sharing based on multipoint IBD information using SIBPAL2. We uncovered findings that suggest linkage to smoking in areas that have also been linked to schizophrenia. These candidate loci are currently under investigation. This study suggests that certain chromosomal regions may have pleiotropic effects for susceptibility to both schizophrenia and smoking.