early detection of autism spectrum disorders in children with attention deficit hyperactivity disorder by modified checklist for autism in toddlers: a pilot study from india

background symptoms of autism spectrum disorders (asd) are commonly observed in children diagnosed with attention deficit/hyperactivity disorder (adhd). these symptoms might underlie social and functional impairment in such children. the existing classification systems do not allow for diagnosing both conditions in children. objectives this study aimed to assess the presence of asd in a hospital-based sample of children diagnosed with adhd and to find the utility of modified checklist for autism in toddlers (mchat) through using parent recall in predicting development of asd. patients and methods a total of 50 children with a diagnosis of adhd, who attended the child guidance clinic of a tertiary care hospital in southern india, were recruited through simple random sampling from july to december 2012. these children were assessed for current asd using childhood autism rating scale (cars) and mchat based on parents recall. to test the diagnostic accuracy of mchat in early detection of asd (index test), cars was used as a reference test. openepi 3.01 software was used for computing sensitivity, specificity, positive predictive value (ppv), negative predictive value (npv), and diagnostic accuracy. results among 50 children, 30 (60%) had scores over the cutoff point of 33 on cars while 38 (76%) had scored over the cutoff point on mchat, qualifying for presence of asd. moreover, presence of asd was associated with older age (p = 0.035), greater risk of medical comorbidities (p = 0.022), lower social quotient on vineland social maturity scale (vsms) (p = 0.001), and poorer global functioning according to children’s global assessment scale (cgas) (p = 0.002). using cars as gold standard, the sensitivity and specificity of mchat in predicting asd were 86.7% and 40.0%, respectively. the ppv and npv of mchat in detecting asd were respectively 68.4% and 66.7%. conclusions asd is present in considerable proportion of children diagnosed with adhd. mchat could be a useful instrument for early detection of children at risk of developing asd.