2.3?|?ProcedureParents were interviewed at home and completed demographic questionnaires during the third trimester of pregnancy. The children were assessed at mean ages of 6, 12, 21 and 33 months in an alternating sequence of home and laboratory visits, with two home visits at age 7.
One postgraduate researcher interviewed the parent and another tested the child on measures of cognition, language and social problem- solving, as well as the CAMGAME.2.4?|?Measures2.4.1?|?Socioeconomic adversityA general index of child’s exposure to maternal factors known to be associated with risk for social adversity was created using polychoric principal component analysis. The maternal experiences that contributed to this index were: (1) the mother not having achieved basic educational attainments (i.
e., the mother having no qualifications or fewer than five GCSEs or equivalent attainments); (2) the mother being 19 years of age or under at the time of child’s birth; (3) the mother not being legally married during the pregnancy; (4) the mother not being in a stable couple relationship during the pregnancy; and (5) the mother’s current occupation being classified as lower status according to the Standard Occupational Classification 2000 (SOC2000; Elias, McKnight, , 1999). All the items contributed to a single component (eigenvalue 3.
84) which explained approximately 77% of the shared variance. Summary factor scores derived from the analysis were used as a proxy for socioeconomic adversity.2.4.2?|?Mothers’ antisocial behaviourMothers reported on their history of arrest as part of the life events section of the Wave 1 questionnaire.
The questionnaire battery at Wave 1 also included a section labelled ‘What I Am Like’, which included items from the screening questionnaire for the International Personality Disorder Examination (IPDE; Loranger et al., 1994). The screening questionnaire associated with the IPDE interview has been used in the UK and in community samples, including a large national sample in Australia (Lewin, Slade, Andrews, Carr, & Hornebrook, 2005).
For the present analyses, a subset of IPDE screening items that corresponded to the DSM- IV criteria for Antisocial Personality Disorder (ASPD) was identified along with an additional set of items measuring DSM- IV symptoms of CD were included in the questionnaire. The conduct symptom items were incorporated into a section of the Wave 1 questionnaire entitled ‘What I Was Like as a Child’. A composite variable created by summing the two individual scales showed an acceptable level of internal consistency, ? = .79, and was further validated by mothers’ reports of their history of arrest, point biserial r (323) = .
56, p < .001.2.4.3?|?Prenatal depressionThe Wave 1 prenatal interview incorporated the mood disorder and anxiety disorder sections of the Schedules for Clinical Assessment in Neuropsychiatry (SCAN; Wing et al.
, 1990), with an additional screen for psychotic symptomatology. Final decisions about clinical diagnoses were made in case conferences with two adult psychiatrists. There was significant agreement between two psychiatrists’ diagnoses of prenatal disorder, ? = .
78, p < .001, and past disorder, ? = .76, p < .001. Dichotomous variables were created to measure presence of DSM- IV mood disorder (Major Depressive Disorder or Bipolar Disorder) in pregnancy. Individual cases were reviewed to exclude individuals presenting in pregnancy with manic symptoms only.
2.4.4?|?Angry aggressiveness in infancyAt 6 months postpartum, up to three informants per family (mothers, fathers, and a third family member or friend) completed a developmental milestones checklist that included a brief four- item scale, the Cardiff Infant Contentiousness Scale (CICS), which was designed to assess infants’ explicit expressions of anger and use of force against their companions (Hay et al., 2010). The four items that comprise the CICS scale are hits out at people; angry moods; bites; and has temper tantrums. The CICS scale had adequate internal consistency (median ? across mothers, fathers, and third informants being .
69), with significant agreement between all possible pairs of informants, with high agreement between parents, r (217) = .51, p < .001. The CICS ratings were validated by direct measures of the infant's distress when confined, that is, strapped into a car seat and observed tendencies to strike out at or grab toys from peers (Hay et al., 2010) and predicted the children's later aggressive conduct problems at age 3 years (Hay et al.
, 2014). CICS factor scores were derived through a measurement model using Mplus 7 whereby a latent dimensional construct was estimated using the maternal, paternal and third informant’s assessments as indicators. These factor scores, analogous to standardized scores, were constrained to have a mean of 0 and SD = 1. Mplus 7 (Muthén & Muthén, 2012) was used to implement this measurement model and calculate a factor score.2.4.
5?|?Time spent playing computer gamesAt age 7, as part of a clinical interview, the Preschool Age Psychiatric Assessment (PAPA; Egger et al., 2006), the parent was asked about the child’s usual activities, including the estimated time spent playing computer games. The interview yielded an ordinal variable ranging from never to three hours or more per day. The variable was dichotomized to contrast those children who played computer games daily versus other members of the sample