A total of 1588 individuals had genotype and phenotype data. The sample was 62.5% female and had a mean age of 36 years. Approximately 12% of the sample was classified as alcohol dependent according to DSM-IV. Figure 1 shows the sample distribution of max drinks, and figure 2 shows the distribution of DSM-IV symptom count. Due to ascertainment, approximately half of the sample was nicotine dependent. Clustering the sample by average genome wide IBD sharing yielded a single cluster, indicating no evidence for population stratification.
