Psychometric properties, factor structure and cross-cultural validity of the quantitative CHecklist for autism in toddlers (Q-CHAT) in an Italian community setting

Background In the past decade, several screening instruments have been developed to detect toddlers at risk for autism, both in clinical and unselected samples.We aimed to assess the validity and cross-cultural stability of the Quantitative CHecklist for Autism in Toddlers (Q−CHAT), a quantitative and normally distributed measure of autistic traits, during routine paediatric developmental surveillance in a large Italian community of toddlers. Methods A group of n = 2400 unselected Italian toddlers were screened by paediatricians during routine well−CHild visits between 18 and 24 months,in three Italian regions, representative of the North, Centre and South of Italy. The psychometric properties and factor structure of the Q−CHAT were explored and compared with published literature from Asia and the UK. Results The total Q−CHAT scores in our sample confirmed a normal distribution. Mean Q−CHAT scores across regions were consistent with those reported in UK studies and likewise, a gender effect was found, with boys scoring higher than girls.We also found a remarkable consistency with the three-factor structure of the Asian Q−CHAT. Internal consistency was acceptable for both the Q−CHAT total score and the three factors. Conclusions Our results confirm the dimensional distribution of autistic traits and related symptoms in unselected populations across different cultures. The Q−CHAT is a valid and reliable dimensional screening instrument to be used within a routine paediatric setting during well-child assessments.The main normative data and factor structure replicated in our sample