All mothers who could read and speak English with children admitted to either of the 2 PICU
study sites (ie, a 12 - bed PICU at a 124 - bed children's hospital within a 720 - bed academic medical center in upstate New York or a 31 - bed PICU at a 235 - bed children's hospital in southwestern Pennsylvania) were eligible to participate if their children 1) had an unplanned medical or surgical admission to the PICU, 2) were between 2 and 7 years of age, 3) were expected to survive, 4) had no
prior ICU admissions, 5) had no cancer, and 6) had no
suspected or diagnosed physical or sexual abuse.
Additionally, based on
prior evidence from behavioural genetics
studies conducted in Western populations, one might
suspect a heightened prevalence of negative affect and related disorders in East Asian populations given the greater prevalence of individuals carrying the S allele.