Reaction time crossover as a marker of schizophrenia and of higher functioning

A factor analysis of reaction time crossover data of 53 schizophrenic patients, 45 first-degree relatives, and 38 controls, previously reported by De Amicis and Cromwell, was performed in order to shed light upon the relationship of crossover to aging, mean reaction time, and general socioeconomic functioning. The aging factor shared variance with getting married and having children, but not with reaction time crossover. Crossover was also found to be independent of reaction time speed among first-degree relatives and control subjects; however, it was correlated with reaction time speed among actively symptomatic schizophrenic patients. Additionally, the relationship of crossover to socioeconomic functioning was found to be negative among the patients, positive among the relatives, and nonexistent among control subjects. Results are discussed in terms of previous reports of higher than normal functioning found in relatives of schizophrenic patients.