Schizophrenic reactions in the Serial Spiral After-Effect Test

A group of 52 schizophrenics, 13 neurotics and 30 normals were studied by means of the Serial Spiral After-Effect Test. Schizophrenics with classical overt symptoms showed significantly higher values compared to neurotics, normals and latent schizophrenics on the residual variability in ten consecutive durations of the after-effect, i.e. the total variability minus the variability ascribable to linear change. Significant correlations were obtained between residnal variability in the Serial Spiral After-Effect Test and psychosis, as assessed by a psychiatric rating scale for the schizophrenics with classical overt symptoms, when the mean level in the Serial Spiral After-Effect Test was checked.