The mean number of DSM-IV symptoms for each represented ethnic group, as well as each phenotypic subgroup is given in Table 4, along with the significance of group differences tested by ANOVA. Overall responses to the DSM-IV items were available for 1051 individuals with a mean symptom count of 1.4 ± 1.8. Within “current frequent smokers” the mean symptom count was 3.3 ± 1.6. No significant differences in DSM-IV symptoms were seen between the sexes, nor between ethnicities. Hispanic individuals tended to endorse fewer symptoms than Caucasians and African Americans, but this was not significant. As expected, number of quit attempts and nicotine dependence were correlated with an r2 = 0.35 (p < 0.001) in the whole sample and r2 = 0.30 (p < 0.001) within current frequent smokers.
