Neurological soft signs in first-episode schizophrenia: State- and trait-related relationships to psychopathology, cognition and antipsychotic medication effects

Background Neurological soft signs (NSS) are proposed to represent both state- and trait-related features of schizophrenia. Method We assessed the course of NSS with the Neurological Evaluation Scale (NES) over 12 months of standardised treatment in 126 patients with first-episode schizophrenia, schizophreniform or schizoaffective disorder, and evaluated their state- and trait-related associations with psychopathology, functionality, cognition and antipsychotic treatment. We considered change scores from baseline to be state-related and endpoint scores to be trait-related. Results Significant effects for time were recorded for all NSS domains. For state-related change-scores greater improvements in sensory integration were predicted by more improvement in working memory (p = 0.01); greater improvements in motor sequencing scores were predicted by more improvement in working memory (p = 0.005) and functionality (p = 0.005); and greater improvements in NES Total score were predicted by more improvement in disorganised symptoms (p = 0.02). There were more substantial associations between trait-related endpoint scores than for state-related change scores. For endpoint scores lower composite cognitive score predicted poorer sensory integration (p = 0.001); higher Parkinsonism score predicted poorer motor co-ordination (p = 0.0001); lower composite cognitive score (p = 0.001) and higher Parkinsonism score (p = 0.005) predicted poorer motor sequencing; higher Parkinsonism score (p = 0.0001) and disorganised symptoms (p = 0.04), and lower composite cognitive score (p = 0.0007) predicted higher NES total score. Conclusions NSS improved with treatment, but were weakly associated with improvements in psychopathology. Studies investigating NSS as trait-markers should ensure that patients have been optimally treated at the time of testing, and should take possible effects of extrapyramidal symptoms into account.