Using the DBC-P Hyperactivity Index to screen for ADHD in young people with autism and ADHD: A pilot study

•We examined if the Developmental Behaviour Checklist Hyperactivity Index could differentiate autism, ADHD and autism + ADHD.•We also compared the behavioural profiles on the DBC between autism, ADHD and autism + ADHD.•The DBC-HI distinguished autism from autism + ADHD with fair sensitivity and specificity.•Individuals with autism+ADHD exhibited a more severe profile of emotional-behavioural disturbance than autism or ADHD alone.•The DBC may be a useful ‘all-in-one’ screening tool to identify comorbidity and the severity of disturbance in autism/ADHD.

This study aimed to (1) determine preliminary validity of the Developmental Behaviour Checklist-Hyperactivity Index (DBC-HI) as a screening measure of combined-type ADHD in autism and ADHD, and (2) compare emotional-behavioural disturbance using the DBC in autism, ADHD and autism + ADHD. Forty-nine age- and PIQ-matched young people [6–18 years; 12 autism, 13 ADHD, 12 autism + ADHD, 12 typically developing] were recruited. Parents completed the Conners-Revised Rating Scale and DBC. The DBC-HI displayed strong internal consistency and good external validity, reliably measuring combined-type ADHD. The DBC-HI distinguished autism from autism + ADHD with fair sensitivity and specificity. Individuals with autism + ADHD exhibited a more severe profile of emotional-behavioural disturbance than autism or ADHD alone. The DBC may be a useful ‘all-in-one’ screening tool to (1) identify comorbidity and (2) determine the severity of emotional-behavioural disturbance in autism and/or ADHD.