All analyses were performed using the Statistical Package for Social Sciences (SPSS) version 14.0 (2005). The three ethnic groups were compared on demographic indicators and clinical characteristics and research participation history, using χ2 goodness-of-fit tests. The item that assessed willingness to participate in genetic research of mental illness was dichotomously recoded (collapsing ‘somewhat’ and ‘strongly’ agree into 1λ=λyes, and collapsing ‘somewhat’ and ‘strongly’ disagree into 2λ=λno). With this recoded item, we used a χ2 test to compare the ethnic groups on willingness to participate, and then within these ethnic groups we examined the demographic and clinical or research factors associated with the willingness to participate.
