Behavior was assessed using the Strengths and Difficulties Questionnaire (SDQ), 21 which is directed at children aged 3 to 4 years. In the SDQ, 25 items in 5 subscales are scored. Four
of these subscales—emotional difficulties score, conduct difficulties score, hyperactivity difficulties score, and peer problems score—are added together to forma total difficulties score
(based on 20 items; maximum score, 40; higher scores indicatemore difficulties). The fifth subscale, the prosocial score, is evaluated separately (5 items; maximum score, 10; higher
scores indicate better prosocial behavior). A cutoff score was defined according to the criteria given for borderline and abnormal in themanual, Scoring the Informant-Rated Strengths
and Difficulties Questionnaire