Characteristics of African American (AA) and European American (EA) samples.

CA: childhood adversity [i.e., (1) parents died before age 6, (2) witnessed or experienced a violent crime (like a shooting or a rape) by age 13, or (3) sexually or badly physically abused by age 13]. AD: alcohol dependence; CD: cocaine dependence; OD: opioid dependence; MjD: marijuana dependence; ND: nicotine dependence. aThe distribution of adversity types in AA cases (with CA) was significantly different from that in EA cases (with CA) by Chi-square test (P≤0.05). bThe distribution of numbers of adversities in AA cases (with CA) was significantly different from that in EA cases (with CA) by Chi-square test (P≤0.05). cThe distribution of comorbid substance dependence (CD, OD, MjD, or ND) in AA cases (with CA) was significantly different from that in EA cases (with CA) by Chi-square test (P≤0.05). dThe distribution of comorbid substance dependence (CD, OD, MjD, or ND) in AA cases (without CA) was significantly different from that in EA cases (without CA) by Chi-square test (P≤0.05).