A quantitative measure for expressed emotion.

The items of the Five Minute Speech Sample, an instrument to elicit relatives' expressed emotion, were investigated in a follow-up study of 120 parents of adolescents with recent-onset schizophrenia. A composite scale was constructed using Mokken scale analysis. From the 9 available items, 6 formed a unidimensional and cumulative scale. This scale was applicable for the total parent group, as well as for fathers and mothers separately. A second scale of 2 items did not meet the criteria for the Mokken model completely and was applicable for the parent group as a whole, but not for fathers and mothers as separate groups. The configuration of the subscales as found with the Mokken scale analysis was comparable with the results of principal component analysis. A quantitative measure may detect smaller differences in expressed emotion than the dichotomous index and expands the possibilities for statistical tests.