The specificity of neurological signs in schizophrenia: a review

This review examines the extent to which neurological signs are more prevalent in schizophrenia patients, compared to mood-disorder patients and healthy subjects, and whether there is a pattern in any of the differences that may be found. We included 17 studies and calculated the weighted mean prevalence of 30 neurological signs. The prevalence of most signs appears to be significantly different between schizophrenia patients and normal controls, but there are fewer differences between schizophrenia and mood-disorder patients. Several signs - poor stereognosis and rhythm tapping - are even more prevalent in mood-disorder patients than in schizophrenia patients. Only lack of extinction, dysdiadochokinesia, poor tandem walk, finger-thumb-opposition and articulation are significantly more prevalent in schizophrenia compared to mood-disorder patients. Impaired motor coordination seems most specific to schizophrenia. The discriminating power of motor sequencing still needs to be studied. So far, there is no evidence of a clearly interpretable pattern of neurological signs distinguishing schizophrenia patients from mood-disorder patients.