Abstract
The current categorical approach has not proved successful in resolving the problem of classifying patients with both affective and schizophrenic features. A dimensional approach is suggested; postulating two interacting factors; "dissociotaxia", a neurointegrative abnormality; and "hyperactivation", an abnormality in activation regulation. The latter factor can convert dissociotaxia to associative dyscontrol and produce mixed schizoaffective features. Clinical-phenomenological, prognostic, genetic-familial, treatment response and biological evidence is reconsidered from this standpoint; and the preferability of the dimensional approach is suggested, both for understanding the underlying psychopathology, and for constructing a different classification system, extensible to other areas of psychiatry.