Interrater reliability of scores derived from two methods for scoring the clock drawing test

Scores on the Clock Drawing Test have long been considered a useful screening tool for neuropsychological dysfunction, and a number of scoring methods have been developed to evaluate various aspects of performance. This study compared quantitative and qualitative scoring by briefly trained students on 145 clock drawings produced by patients in a geriatric psychiatry outpatient clinic to estimate the interrater reliability of the methods, user's acceptance of the methods, and whether the methods provide differential diagnosis. Both systems showed acceptable interrater reliability. Using the quantitative method, raters scored drawings by patients with organic mental disease as more impaired than those patients diagnosed as depressed or schizophrenic. Results suggest that the Clock Drawing Test is a reliable screening tool for cognitive impairment in a geropsychiatric population, but the scoring methods examined do not yet appear psychometrically sound enough to provide a differential diagnosis.