Critical evaluation of cognitive dysfunctions as endophenotypes of schizophrenia

OBJECTIVE: Cognitive dysfunctions are potential endophenotypes of schizophrenia. The aim of this study was to investigate whether recent evidence indeed suggests that cognitive dysfunctions are potent indicators of specific genetic traits that represent susceptibility for schizophrenia. METHOD: Studies including large, well-defined samples and controlled cognitive assessment have been reviewed. RESULTS: Evidence suggests that schizophrenia patients and their unaffected biological relatives are impaired in several cognitive domains, including working memory, executive functions, sustained attention, verbal episodic memory, processing of visual and auditory stimuli, and smooth pursuit eye movements. However, these impairments are present only in a limited proportion of subjects, showing low specificity and sensitivity and high variability. Linkage with specific genes is weak. CONCLUSION: Although some results are promising, at present cognitive dysfunctions cannot be considered as highly sensitive and specific endophenotypes of schizophrenia.