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Since the earliest days of classifying schizophrenia, attempts have been made to assign symptoms to one of two broad classes, generally known as positive and negative. Positive symptoms are those that are characterized by the presence of abnormal behavioral phenomena, such as delusions or hallucinations. Negative symptoms, on the other hand, are deficits or diminutions in normal function, such as loss of emotional affect, will, or speech. In recent years, this classification scheme has been called into question, with some claiming that the two symptom sets are not independent, and others suggesting yet a third category of symptoms known as 'disorganization.' Two studies are described which were intended first, to examine the independence of positive and negative symptoms, and second, to determine the status of the symptoms of thought disorder, catatonia, and cognitive impairment within the context of the positive:negative scheme. In the first study, 62 schizophrenics were evaluated using two scales, the High Royds Evaluation of Negativity (HEN) and the Schedule for Assessment of Negative Symptoms (SANS), to measure negative symptoms. A third scale was used to measure all psychiatric symptoms, and correlations between various scores were calculated. Similarly, the second study, involving 80 schizophrenic patients, measured negative symptoms as well as cognitive function and motor disorders. The presence of negative symptoms could not be correlated with positive symptoms, confirming the validity of a positive:negative dichotomy. Based upon the results of the first study, it is supposed that negative symptoms are more fundamental in schizophrenia, as they correlate most consistently with the diagnosis. The results of the second study reveal that formal thought disorder appears to be a positive symptom, as does poverty of content of speech, even though it appears to be a deficit. It is also concluded that catatonia can be divided into both positive and negative symptomatology. Cognitive impairment seems to be an ill-defined set of conditions that are affiliated with various schizophrenic symptoms. (Consumer Summary produced by Reliance Medical Information, Inc.)

A review of research on the negative symptoms of schizophrenia reveals confusing variations in experimental methodology and diagnostic criteria, as well as inconsistent results. Negative symptoms are usually defined by blunted mood and emotions (affect), poverty of speech and slow movement. Studies of the prognostic or predictive value of negative symptoms assessed during an acute schizophrenic episode have been inconclusive. However, studies that have looked at symptoms occurring during nonacute or posthospitalization periods have found negative symptoms to be strong predictors of poor overall functioning at two- and five-year follow-up evaluations. This may be because negative symptoms during postacute episodes are less likely to be secondary symptoms related to neuroleptic (antipsychotic) medication side-effects, or responses to psychosis. Studies examining social withdrawal and functioning deficits prior to first schizophrenic hospital admission suggest a moderate ability to predict the eventual development of negative symptoms. The overall prognostic utility of negative symptoms in evaluating illness outcome is much more moderate than previously thought. Studies also suggest that more changes occur in negative symptoms over time than previously expected. We still do not know whether or not negative symptoms stabilize or become more predominant during the later course of illness, but the degree of symptom instability demonstrated by recent studies argues against a model relating all negative symptoms to brain abnormalities. (Consumer Summary produced by Reliance Medical Information, Inc.)

In order to evaluate relationships between depression, impaired mood and emotionality (affect), and the positive and negative symptoms of schizophrenia, 37 newly admitted, young urban patients of mixed ethnic backgrounds (with an average age of 24 years) and an illness onset of two years or less were studied and followed-up for two years. During the first two weeks of their first schizophrenic admission, they were given a battery of tests to assess affect, attention span, drug-induced neurological symptoms, and positive and negative syndrome factors. A positive symptom score was obtained by summing ratings of delusions, thought disorder, paranoia, hallucinations, excitability, grandiosity, and hostility. A negative score added ratings for blunted affect, emotional withdrawal, passivity, poor abstract thinking, and poverty of speech. Factor analysis of the initial tests revealed three distinct affective clusters: (1) emotional unrelatedness; (2) immobility of facial and gestural expression; and (3) inappropriate affect. The first two factors were significantly related to each other and to depression. Depression was also significantly related to concurrent negative symptoms. The third factor was only significantly related to high positive scores. A two-year follow-up evaluation revealed that an initial high depression rating was significantly related to better overall level of functioning, social relations and occupational adjustment. Poor premorbid functioning (that is, before onset of the illness) was found to be highly related to (1). At the onset of the study, depression was significantly higher among nonparanoid patients. After two years, paranoia was only significantly related to an initial high rating on factor (3). Results suggest that the affective profiles of young, acute schizophrenics include three distinct dimensions with concurrent and predictive significance. (Consumer Summary produced by Reliance Medical Information, Inc.)