Neurocognitive and clinical dysfunction in adult Chinese, nonpsychotic relatives of patients with schizophrenia: Findings from the Changsha study and evidence for schizotaxia

Abstract

Many first-degree relatives of patients with schizophrenia demonstrate deficits in neurocognitive, social, clinical and other dimensions, in the absence of psychosis. Based on a reformulation of Meehl's concept of "schizotaxia" as a clinically meaningful syndrome reflecting liability to schizophrenia, we proposed research criteria in relatives focused on negative symptoms and neurocognitive deficits. Here we assess validity of the syndrome in a sample of Chinese adult relatives by assessing measures of concurrent validity, and by using cluster analysis to test the hypothesis that relatives could be grouped into distinct schizotaxic and non-schizotaxic subgroups based on our diagnostic criteria. Thirty community comparison subjects (CCS) and 189 relatives were evaluated with measures of clinical, cognitive, medical and social function at the Mental Health Institute, Second Xiangya Hospital of Central South University, Changsha (Hunan, China), as part of a larger study to identify and ameliorate symptoms of schizotaxia. Using modified research criteria based on negative symptoms and neurocognitive deficits, 103 relatives did not meet criteria for schizotaxia, and 86 did. The cluster analysis confirmed a two-group solution that corresponded to our non-schizotaxic and schizotaxic groups, but it increased the non-schizotaxic group to 135, and reduced the schizotaxic group to 53. Both schizotaxic groups, but especially the cluster-derived group, showed significant impairment in a variety of independent (i.e. non-criterion related) measures of clinical and social function. These findings provide additional validity for a liability syndrome, and for its utility as an intervention target for strategies aimed at ameliorating both its core and its associated symptoms.