Deficit symptoms in schizophrenia: negative symptoms versus neuroleptic‐induced deficits

Definitions of negative symptoms and deficit syndromes are reviewed in this article; rating scale criteria (the Scale for Assessment of Negative Symptoms and the Positive and Negative Syndrome Scale); Crow's type II syndrome; Carpenter's deficit syndrome; and the draft of DSM‐IV. The core negative symptoms identified by these investigators also describe the neuroleptic‐induced deficit syndrome (NIDS). Study designs and assessment methods to distinguish NIDS from the symptoms of schizophrenia are presented. Assessment methods include rating scales and a novel method that uses descriptive symptom vignettes. Designs include neuroleptic discontinuation studies, dose comparisons and comparison of atypical antipsychotic medicines to typical neuroleptic drugs.