Is the Conners' continuous performance test helpful for assessing attention deficit hyperactivity disorder in a clinical setting?

Background: Despite lacking validation for Norwegian populations, the Conners Continuous Performance Test II (CCPT-II) is applied to almost one-third of children receiving an ADHD diagnosis. However, evidence of the CCPT-II's ability to differentiate between children with and without ADHD is contradictory. Thus, this study examines how CCPT-II results correlate with ADHD symptoms reported by mothers and teachers in a sample representing ordinary child and adolescent mental health services and explores the extent to which the CCPT-II influences the diagnostic result.

Methods: Correlations between CCPT-II results and ADHD Rating Scale scores and a clinical diagnosis of ADHD were analysed in children aged 6-15 years ( = 69) referred to a child and adolescent psychiatric outpatient clinic.

Results: Total ADHD symptom scores rated by mothers correlated with hit reaction time (HRT) block change (.260), HRT inter-stimulus interval (ISI) change (.264) and CCPT-II overall index (.263), while hyperactivity subscale scores correlated with omissions (.285), HRT (.414) and variability (.400). In teachers' ratings, total ADHD and both subscale scores correlated with commissions (.280-.382), while hyperactivity scores correlated with variability (.265). A higher number of commissions was the only significant difference in CCPT-II performance between children diagnosed with and children without ADHD.

Conclusions: Correlations between CCPT-II results and ADHD symptoms were all small to moderate. As such, CCPT-II results should be interpreted with caution, because they correspond to a limited degree with other sources of information.