Despite the widespread belief that neuropsychological decline is a cardinal feature of the progression from the premorbid stage to the chronic form of schizophrenia, few longitudinal studies have examined change in neuropsychological functioning from before to after illness onset. The authors examined whether neuropsychological decline is unique to schizophrenia, whether it is generalized or confined to particular mental functions, and whether individuals with schizophrenia also have cognitive problems in everyday life.

Meier MH, Caspi A, Reichenberg A, Keefe RSE, Fisher H, Harrington HL, Houts R, Poulton R, Moffitt T. Neuropsychological decline in schizophrenia from the premorbid to post-onset period: Evidence from a population-representative longitudinal study.  American Journal of Psychiatry, 2013; 171(1): 91-101.  (PMCID:  PMC3947263).