Potential endophenotype for schizophrenia: neurological soft signs.
BACKGROUND
Neurological soft signs (NSS) are suggested as a candidate endophenotype for schizophrenia. This article aims to review relevant literature and discuss the role of NSS in understanding schizophrenia.


METHODS
This is an update on a review article published in 2003. Articles from 2003 onwards were specifically reviewed and discussed with relevance to the role of NSS as endophenotype for schizophrenia.


RESULTS
Consistent data suggest an excess of NSS in schizophrenic patients. NSS appear to be related to schizophrenic symptoms, in particular negative symptoms and disorganisation. Information on NSS and demographic correlates is scarce, and the confounding effects between age, education and intelligence on NSS constitute an important gap in current knowledge. Longitudinal data suggest NSS as both a trait and state variable in the course of disease. NSS are not specific with regard to diagnosis, although there are claims that individual sub-components may be more specific. The weight of evidence raises question on the specificity of NSS for schizophrenia.


CONCLUSIONS
The usefulness and feasibility of NSS as a specific endophenotype target for schizophrenia is unclear. However, NSS remain an important feature and symptom correlate of schizophrenia. Future research should focus on delineating the effects of NSS from those of confounding demographic variables, and the stability of NSS over the course of illness to elucidate its role in schizophrenia.
Hui
Christy Lm
CL
Department of Psychiatry, The University of Hong Kong, Hong Kong.
Wong
Gloria Hy
GH
Chiu
Cindy Py
CP
Lam
May Ml
MM
Chen
Eric Yh
EY
D006801:Humans; D001523:Mental Disorders; D009460:Neurologic Examination; D010641:Phenotype; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics*; D012680:Sensitivity and Specificity