The positive-negative distinction in schizophrenia. Review of natural history validators.

A review of the interaction between the positive-negative symptom distinction in schizophrenia and multiple measures of illness natural history reveals some redundant and compelling patterns. Negative or deficit symptoms are often associated with inferior social/instrumental functioning premorbidly, more abnormal voluntary/involuntary movements at illness presentation, and poorer long-term outcome when present beyond the early phase of illness. Negative symptoms are semi-independent of positive symptoms. They are variable early in the illness but accrue in severity, stability, and prognostic weight with time. The nature of the processes that generate negative symptoms and their specificity to schizophrenia remain to be elucidated. Nevertheless, it is clear that negative symptoms are a common and valid component of schizophrenia and deserve recognition as such in our nosology.