Although children with a greater number of autistic traits are likely to have other mental health problems, research on the association between earlier autistic traits in preschool children and later emotional/behavioral outcomes is scarce. Using data from 189 Japanese community-based children, this study examined whether autistic traits at age 5 were related to emotional/behavioral outcomes at age 7. The results showed that prior autistic traits were subsequently associated with all emotional/behavioral domains. After controlling for baseline emotional/behavioral scores autistic traits continued to predict later emotional symptoms and peer problems. This study highlights that in addition to clinical ASD, it is also important to focus on subthreshold autistic traits in preschool children for better subsequent emotional/behavioral outcomes.

To determine the best discriminative items for identifying young children with autism spectrum disorders (ASD), we conducted a secondary analysis using longitudinal cohort data that included the Japanese version of the 23-item modified checklist for autism in toddlers (M-CHAT-JV). M-CHAT-JV data at 18 months of age and diagnostic information evaluated at age 3 or later from 1851 Japanese children was used to isolate six highly discriminative items. Using data from two different community samples (n = 1851, n = 665) these items were shown to have comparable psychometric values with those of the full version. Our results suggest that these items might work as a short form screener for early identification of ASD in primary care settings where there are time constraints on screening.

The recent development and use of autism measures for the general population has led to a growing body of evidence which suggests that autistic traits are distributed along a continuum. However, as most existing autism measures were designed for use in children older than age 4, to date, little is known about the autistic continuum in children younger than age 4. As autistic symptoms are evident in the first few years, to address this research gap, the current study tested the preschool version of the Social Responsiveness Scale (SRS-P) in children aged 2 to 4 1 =2 years in clinical (N 5 74, average age 40 months, 26-51 months) and community settings (N 5 357, average age 39 months, 25-50 months) in Japan. Using information obtained from different raters (mothers, other caregivers, and teachers) it was found that the scale demonstrated a good degree of internal consistency, inter-rater reliability and test-retest reliability, and a satisfactory degree of convergent validity for the clinical sample when compared with scores from diagnostic "gold standard" autism measures. Receiver operating characteristic analyses and the group comparisons also showed that the SRS-P total score discriminated well between children with autism spectrum disorder (ASD) and those without ASD. Importantly, this scale could identify autistic symptoms or traits distributed continually across the child population at this age irrespective of the presence of an ASD diagnosis. These findings suggest that the SRS-P might be a sensitive instrument for case identification including subthreshold ASD, as well as a potentially useful research tool for exploring ASD endophenotypes. Autism Res 2017, 10: 852-865.