Positive and negative symptoms: historical and conceptual aspects

The re-emergence of interest in negative symptoms during the past decade has generated a creative period for the study of psychopathology in schizophrenia. Increasingly, a relative balance has been restored to descriptive psychopathology, giving more equal emphasis on florid colorful symptoms such as delusions and hallucinations as well as the more debilitating negative symptoms. An emphasis on considering the neural mechanisms that may underlie both positive and negative symptoms has led to a more focused approach to asking questions about psychopathology, particularly emphasizing the importance of longitudinal perspectives and the possible interaction between treatment effects and psychopathology. These developments cannot help but improve the quality of both basic and clinical research in schizophrenia during the next decade.