Objectives: Examine the distribution of total SCQ, SCQ domain and individual item scores in a general population birth cohort.
Methods: : Children in this analysis were drawn from the Autism Birth Cohort (ABC), a subset of a prospective birth cohort in Norway (the MoBa). Children whose parents completed a questionnaire including the 40-item SCQ at child age 36-39 months were included (n=29,093). SCQ total scores(SCQ39-M) and social impairment, repetitive/ritualistic behaviors, and communication impairment domain scores were derived per manual guidelines (SCQ39-M). The association of child and parent characteristics, including sex, birth order (first- vs later-born), maternal age (< 25, 25-34, ≥ 35 years), maternal education (< 12 years, 12 years, 13-16 years, 17+ years), and referral status (questionnaire item regarding referral for educational/habilitation/psychiatric evaluation) with SCQ profiles were examined.
Results: The sample was comprised of 50.9% boys; nearly half were first-born. The mean age of mothers was 30.16 ± 4.4 years. 2.8% of children had been referred for community clinical/educational assessments. The mean of SCQ39-M scores was 6.31 ± 3.31. Only 1.2% received a total of 0 (i.e., no reported symptoms); 1.5 % had scores ≥ 15. Thirteen SCQ items were endorsed in >20% of children, and 9 of these were reported in >33% (echolalia, inappropriate questions, pronoun reversal, verbal rituals, compulsions and rituals, use of others boy, repetitive use of objects, complex mannerisms, friends).
Boys had higher total SCQ39-M scores than girls (6.75 v 5.85). This pattern was reversed among nonverbal children, where total scores were greater among girls than boys (9.67 v 8.86). First-borns had higher SCQ39-M scores than later-born children (6.83 v 5.89), largely reflecting greater number of repetitive/ritualistic behaviors. Consistent with this finding, advancing maternal age was associated with decreasing total symptom reports. Furthermore, low maternal education was associated with higher SCQ39-M total scores. Children referred for services (education, habilitation, psychiatry) reported more symptoms than non-referred children
SCQ patterns are associated with sex, birth order, maternal age, maternal education and referral history. Expanded awareness of factors influencing reporting, and factors regulating behaviors commonly endorsed for preschool children will help refine autism screening tools such as the SCQ and enhance generalizability of these instruments for detection of autism risk very young children.