Observer -ratings of ADHD symptoms in adults: Normative data, factor structure and convergent validity

Obtaining collateral reports from significant others has become increasingly recognized as an important component of assessments for ADHD in adults. The Conners Adult ADHD Rating Scales (CAARS) include both self-report (CAARS-S) and observer-report (CAARS-O) forms. In contrast to the CAARS-S, fewer data have been published with respect to the factor structure, norms, and psychometric properties of the CAARS-O. Thus, the primary aim of this study was to examine how well the 4-factor structure obtained for the CAARS-S could be replicated with data collected from observers reporting on individuals whom they know well using the CAARS-O. The secondary aims included describing the existing norms for the CAARS-O, testing for age and gender effects within those normative data, and examining convergent validity by correlating self- and observer-report data collected on the same subjects. Analyses were based on archival data sets collected as part of the development and norming of the CAARS. These included a sample comprised of 724 adult collateral informants describing 328 men and 396 women using the CAARS-O as well as a sample of 188 adults who completed the CAARS-S and who were also rated on the CAARS-O by a significant other. Results of the confirmatory factor analysis indicated that the 4-factor model found for the CAARS was replicated in the CAARS-O data, with excellent fit for both men and women. Analyses of the normative data for the CAARS-O yielded significant age and gender effects. With respect to convergent validity, significant moderate to high correlations were found between the CAARS-O and CAARS-S across all four factors. Implications of these findings for the conceptualization, assessment, and future study of adult ADHD are discussed.