The composition of the negative syndrome of chronic schizophrenia.

The clinical features of patients who satisfy a variety of criteria for the negative syndrome can be arranged in five groups of phenomena: (a) poverty of thought and speech, (b) blunted affect, (c) decreased motor activity, (d) apathy and abolition, and (e) diminished interpersonal interaction. We have shown that depressed mood and depressive cognition are not related to the negative syndrome, but there is some overlap between the specific phenomena of depressive illness and negative symptoms in schizophrenia. Items measuring cognitive impairment have a moderate correlation with the negative syndrome, but the negative syndrome accounts for less than half of the variance of cognitive performance. These items that define the negative syndrome can be as reliably measured as depressive and positive symptoms.