Neurological soft signs as candidate endophenotypes for schizophrenia: A shooting star or a Northern star?

The crucial role of neurological indicators in schizophrenia has been recognized as among the “target features” that encompass the idea that genetic and non-genetic processes lead to neurointegrative defects later manifested in neurocognitive systems. In addition, aberrant neurological indicators have also been suggested as potential endophenotypes in schizophrenia. In the current paper, we review evidence for the utility of quantifiable neurological soft signs as potential endophenotypes for schizophrenia spectrum disorders. We start by defining endophenotypes and justifying their utility. We highlight the key criteria that must be met for an endophenotype to be useful and assess the extent to which the manifestations of neurological soft signs meet these criteria. Finally, we recommend areas in which additional research should be done to further elucidate the potential use of neurological soft signs for schizophrenia research.