The progress of research on cognitive dysfunction in psychotic disorders, especially in schizophrenia, has offered new perspectives on their pathophysiology, diagnosis and treatments. Although there have been many modern advances in comprehensive treatment of these diseases, meta-analysis of the recovery rate has revealed it to be inadequate. This is due, in part, to excessive emphasis on the positive psychotic symptoms in diagnosis and treatment, resulting in lack of attention to the negative and cognitive symptoms affecting recovery. Indeed, several components of neurocognition, such as attention/vigilance, processing speed and reasoning or learning/memory, are entwined with numerous aspects of daily living activities, including community function, social behavior, problem-solving and social skills. The lifetime trajectory of cognition in psychotic disorders suggested by recent epidemiologic and prospective follow-up studies consists of early cognitive dysfunction prior to childhood, and developmental delays in cognition during adolescence and early adulthood before the onset of illness. The former may be non-disease-specific pathology affecting the severity, whereas the latter may be disease-specific core pathology. Furthermore, as cognitive dysfunction is unchanged just before and at least 5 years after the onset of illness, schizophrenia is likely a neurodevelopmental disease and not neurodegenerative. Schizophrenia may be a heterogeneous constellation of syndromes, quantitatively and qualitatively characterized by cognitive dysfunction, which can be divided into 3 or 4 cognitive subgroups that are not detected by the DSM or ICD diagnosis system. To overcome this heterogeneity, and develop individualized and precise treatments for psychotic disorders, it is essential that they are classified based on pathophysiology.
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