Differential effect of environmental adversity by gender: Rutter's index of adversity in a group of boys and girls with and without ADHD

Objective: The effect of gender in mediating the association between environmental adversity and risk of attention-deficit hyperactivity disorder (ADHD) and associaied impairments was examined in this study. Method: 280 probands with ADHD and 242 healthy comparison probands of both sexes aged 6 to 17 years were studied. The association between Rutter's indicators of adversity (e.g., family conflict, social class, family size, maternal psychopathology, and paternal criminality) and ADHD, comorbidity, and functioning was tested. Results: In both genders, higher levels of environmental adversity were associated with a greater risk for ADHD and other comorbidity in a dosedependent manner (i.e.. the risk for ADHD increased as the number of risk factors increased). Gender did. however, modify learning disability and global functioning, as more detrimental effects were observed in boys than in girls. Low social class, maternal psychopathology, and family conflict were significantly associated with functional impairment and psychopathology in the probands, with control for maternal smoking during pregnancy, proband ADHD status, parental ADHD, and gender. Conclusions: Risk for ADHD and associated morbidity was increased by psychosocial adversity in general and by low social class, maternal psychopathology, and family conflict in particular independent of gender and other risk factors. However, gender did modify the risk for adverse cognitive and interpersonal outcomes in that boys were more vulnerable to ADHD than girls. Separating the effects of genetics from those of the environment is difficult; thus, these results must be seen as provisional until they are confirmed by twin and adoption studies.