Cannabis and neurological soft signs in schizophrenia: absence of relationship and influence on psychopathology

Abstract

Background: Cannabis is a possible risk factor for the onset of schizophrenia and can induce neurocognitive, behavioural and motor co-ordination alterations. The aim of this study was to evaluate the role of cannabis in the occurrence of neurological soft signs (NSS) and, considering that this drug has been related to positive symptoms, whereas NSS have been linked to negative symptoms, we also examined the role of clinical features.

Methods: The study investigated NSS in 25 male cannabis-consuming and 25 male non-consuming schizophrenic patients, using the Neurological Evaluation Scale. Clinical features were studied using SANS and SAPS.

Results: Significant differences emerged after comparison analysis, with more NSS in non-consuming patients. The SANS subscales Alogia and Anhedonia-asociality were also statistically significant in this group of patients.

Discussion: If non-consuming patients show a higher incidence of both NSS and negative symptoms, which, according to the literature, seem to be associated, then these findings suggest that NSS are relatively independent from cannabis, but not from clinical features.