“…The scales (and mean Cronbach alpha across informants) included measures of both internalizing problems: anxiety (4 items, Mα = 0.72, e.g., being nervous, high-strung or tense), social withdrawal (3 items, Mα = 0.68, e.g., prefers to play alone rather than with other children), and emotional problems (3 items, Mα = 0.69, e.g., has trouble enjoying him or herself); and externalizing problems: opposition (3 items, Mα = 0.51, e.g., punishment doesn't change the child's behavior), physical aggression (4 items, Mα = 0.75, e.g., physically aggresses people), reactive aggression (4 items, Mα = 0.75, e.g., reacts aggressively when someone takes a personal belonging, for example by hitting, pushing, or slapping another child), proactive aggression (3 items, Mα = 0.55, e.g., scares other children to get what is wanted), indirect aggression (3 items, Mα = 0.69, e.g., when angry at someone, tries to get others to dislike the other person), and ADHD symptoms (7 items, Mα = 0.86, e.g., cannot settle on anything for more than a few moments; is impulsive/acts without thinking; is inattentive). These validated scales (89,91) have been shown to be sensitive to various environmental, familial, and perinatal risk and protective factors (95)(96)(97)(98)(99) as well as to early sleep patterns (100). The instrument was completed by the participants themselves at 11 years of age as well as by each child's father and teacher in order to get a complete description of their difficulties across the social context.…”