The psychopathology of schizophrenia: an integrated view on positive symptoms and negative symptoms

Interest in the distinction between positive and negative symptoms has reached a peak in the last decade and has led to research in different fields like phenomenology, ethiopathogenesis, treatment, course and outcome. Which symptoms are considered positive or negative varies across different authors, although there seems to be agreement on a core syndrome. The definition problems can be also found in the rating scales used for measuring positive and negative symptoms. The positive/negative distinction may represent different manifestations of a common underlying process. It also may suggest the existence of different pathophysiologies in schizophrenia. Since both positive and negative symptoms are frequent in schizophrenia, they are most likely not completely independent. The negative/positive syndrome is not sufficient to describe the dimensions of the complex phenomenology of schizophrenia. Among others, a depressive syndrome needs to be integrated. There is much controversy concerning the course of positive and negative symptoms over time. In subacute and chronic patients the negative syndrome seems to be more stable than the positive syndrome. The differentiation between primary and secondary negative symptoms seems to have great relevance to clinical and research aspects. This differentiation is an important factor in the interpretation of neuroleptic trials on negative symptoms. One way of differentiating between direct and indirect drug effects on negative symptoms is to use sophisticated statistical procedures, for example path analysis.