Prospective evaluation of neurological soft signs in first-episode schizophrenia in relation to psychopathology: state versus trait phenomena

Background. Although patients with schizophrenia have increased rates of neurological soft signs, few studies have examined prospectively their trait or state characteristics in relation to psychopathology. Method. In a prospective study of 97 patients with first-episode schizophrenia (DSM-IV criteria) we assessed neurological soft signs and psychopathology at presentation and at 6 month follow-up for 73 cases. To establish whether soft signs were associated with variations in clinical state, neurological soft signs were measured using two validated examinations (Neurological Evaluation Scale and Condensed Neurological Examination); psychopathology was assessed using the Positive and Negative Syndrome Scale. Results. There was significant improvement in overall neurological function, primarily in motor-related and cortical signs, which were associated with improvement in psychopathology. Conversely, ‘harder’ signs were unrelated to improvement in psychopathology. Conclusions. Neurological soft signs in schizophrenia are heterogenous. Motor and cortical signs evidence state-like characteristics and vary with clinical course, while ‘harder’ signs evidence more static, trait-like characteristics in accordance with a neurodevelopmental basis.