The concept of deterioration has always been central to schizophrenia, and forms a cornerstone of current diagnostic and conceptual thinking (e.g. DSM–III; Crow, 1985; Weinberger, 1987). Recently, there has been a renewal of interest in the deficits of schizophrenia, with attempts to identify, classify, and measure the relevant abnormalities. According to current thinking (Crow 1985; Wing, this volume) negative symptoms i.e. deficits in emotion, volition and social interaction, represent a distinctive cluster of impairments with aetiological, prognostic and therapeutic significance. Verification of this view of course requires reliable and valid measures of negative symptoms.