Neurological soft signs in early stage of schizophrenia associated with obsessive-compulsive disorder

Given that the obsessive-compulsive disorder (OCD) occurs with a much higher frequency in schizophrenia than in the general population, and, both schizophrenia and OCD are presumed to be neurodevelopmental disorders, the hypothesis of a distinct subtype of schizophrenia, the "schizo-obsessive" one, was raised.

Considering the neurological soft signs as neurobiological markers in schizophrenia, the aim of this study was to verify the hypothesis of the existence of this "schizo-obsessive" endophenotype of schizophrenia, by using the Neurological Evaluation Scale (NES) in patients with schizophrenia.

The study was conducted in a transversal manner and consisted of the assessment of 64 patients with the maximum age of 26 years, who fulfilled the DSM IV-TR criteria of schizophrenia and/ or OCD, the assessment performed both from the social-demographic view, as well as neurologic, by means of the NES scale.

Patients with schizophrenia and OCD proved to have, a significant family history from a static point of view, more loaded by affective disorders, but also by schizophrenia and OCD spectrum disorders, compared to pure schizophrenics. They also proved to have a significant higher educational level and a better occupational functioning than those schizophrenic patients without OCD, despite the similarity of the number of hospitalizations episodes or the disease duration to date. Ratings on the NES scale differentiate the group of patients with schizophrenia and OCD as having the highest scores on all subscales, scores much closer to those obtained by the group of patients with schizophrenia only, the only difference with statistical significance being recorded on the sequencing subscale of complex motor acts. The analysis of cluster through linear discriminant analysis allowed the classification of patients in the 3 groups with a probability of 89.06% and 76.56% for cross-validation.

The results regarding neurological soft signs suggest that the presence of OCD in schizophrenic patients is due to peculiarities in fronto-basal ganglia circuits with possible origins in neurodevelopmental abnormalities. We considered that the early detection of neurological soft signs and their dynamic monitoring could provide useful information on the evolution of schizophrenia. Future research should take into account larger groups of patients to investigate the relationship between neurological soft signs and brain neuroimaging data, as well as the results provided by neuropsychological investigations customed in this subgroup of schizophrenia.