Neurological Examination Abnormalities (NES) are quantified by measuring subtle, partially localizable (cerebello-thalamo-prefrontal cortical circuit) and heritable neurological signs comprising sensory integration, motor coordination and complex motor sequencing that are associated with first-episode psychosis (FEP). A few studies have evaluated NES longitudinally and as a predictor for diagnostic and response classification, but these studies have been confounded, underpowered and divergent. We examined (1) baseline and longitudinal NES differences between diagnostic and year 1 response groups; (2) if NES predicts diagnostic and response groups and (3) relationships between clinical variables and NES measures in antipsychotic-naïve FEP.

NES and clinical measures were obtained for FEP-schizophrenia (FEP-SZ, n = 232), FEP non-schizophrenia (FEP-NSZ, n = 117) and healthy controls (HC, n = 204). Response groups with >25% improvement in average year 1 positive and negative symptomatology scores were classified as responsive (n = 97) and <25% improvement as non-responsive (n = 95). Analysis of covariance, NES trajectory analysis and logistic regression models assessed diagnostic and response group differences. Baseline and longitudinal NES relationships with clinical variables were performed with Spearman correlations. Data were adjusted for age, sex, race, socioeconomic status and handedness.

Cognitive perceptual (COGPER) score was better than repetitive motor (REPMOT) at differentiating FEP-SZ from FEP-NSZ and distinguishing responders from non-responders. We identified significant group-specific associations between COGPER and worse GAF, positive and negative symptomatology and some of these findings persisted at 1-year assessment.

NES are an easy to administer, bedside-elicited, endophenotypic measure and could be a cost-effective clinical tool in antipsychotic-naïve FEP.

Neurological soft signs (NSS) are a group of minor non-localisable neurological abnormalities found more often in patients with schizophrenia. The aim of the current study was to test for the effect of gender, age, parental age, age at onset and clinical symptomatology on NSS.

The study sample included 133 patients suffering from schizophrenia according to DSM-IV-TR (77 males and 56 females; aged 33.55±11.22 years old) and 122 normal controls (66 males and 56 females; aged 32.89±9.91 years old). The assessment included the Neurological Evaluation Scale (NES), and a number of scales assessing the clinical symptoms and adverse effects especially extrapyramidal. The statistical analysis included exploratory t-test, simple linear regression analysis, analysis of covariance and the calculation of correlation coefficients.

The results of the current study confirm that NSS are more frequent in patients with schizophrenia in comparison with normal controls (Wilks=0.622, p<0.0001), but do not support an effect of gender, age, age at onset, paternal or maternal age, education, medication status or clinical subtype of schizophrenia on NES scores.

Overall these results suggest that NSS constitute an independent (from the rest of symptoms), core (present in the vast majority of patients) and trait (unrelated to age and probably to the stage of schizophrenia) symptom of schizophrenia which could be of value in the clinical assessment and research of schizophrenia. Overall these results are not in full accord with the literature, but they could serve to fill in gaps and inconsistencies observed so far.