Preliminary validity data on the Rasch Manic-Depressiveness Scale

The 18-item Manic-Depressiveness Scale was revised via a Rasch top-down purification' procedure to provide a new 12-item scale with no significant age or sex bias. Application of this scale to previously collected data indicated that patients with manic-depression and schizophrenia receive comparable scores, which are significantly higher than those of a control group of students. Moreover, for a subgroup of patients with manic-depression, scores correlated .55 (p<.001) with number of manic-depression-relevant medications being taken. These findings lend support to the validity of the Rasch Manic-Depressiveness Scale as a general measure of psychoticism and psychiatric status.