The goal of this exploratory study was to determine the role of shared genetic and environmental influences on the phenotypic correlations between brain structure and cigarette pack-years. This is one of the first studies to address the relationship of brain structure and chronic smoking. These results are expected to guide future genetic association studies in neuroimaging and smoking-related behaviors. Given the loss of all significant results after correction for multiple testing, cautious interpretation and additional replication in other populations is suggested. Nevertheless, significant results prior to FDR adjustment highlight several interesting features of the etiology of nicotine dependence that have been reported elsewhere in the nicotine dependence literature. We summarize and discuss these results below and identify areas for additional study.
