Long-term administration of the low-dose risperidone in schizotaxia subjects

Experimental Medicine in Psychiatry New Approaches in Schizophrenia, Depression and Cognition

The use of experimental medicine studies to bridge the gap between Phase 1 and 2 drug trials and so to enhance translation of basic neuroscience studies using experimental animals to the clinic is proposed. Illustrative examples are provided for affective disorders and schizophrenia in relation also to cognitive dysfunction.

Development of liability syndromes for schizophrenia: where did they come from and where are they going?

Three decades after Paul Meehl proposed the term "schizotaxia" to describe a conceptual framework for understanding the liability to schizophrenia, Ming Tsuang et al. at Harvard University reformulated the concept as a clinical syndrome with provisional research criteria. The reformulated view relied heavily on more recent data showing that many non-psychotic, un-medicated biological relatives of individuals with schizophrenia showed difficulties in cognitive and other clinical functions that resembled those seen in their ill relatives. The reformulation raised questions about both whether and when liability could be assessed validly in the absence of psychosis, and about the extent to which symptoms of liability are reversible. Both questions bear on the larger issue of early intervention in schizophrenia. This article reviews the efforts of Tsuang et al. to conceptualize and validate schizotaxia as one such syndrome of liability. Towards this end, liability is considered first more generally as an outcome of interactive genetic and environmental factors. Liability is then considered in the context of endophenotypes as a concept that is both broader and is potentially more specific (and predictive) than many DSM or ICD diagnostic symptoms. Liability syndromes are then considered in the context of their proximity to illness, first by reviewing prodromal syndromes (which are more proximal), and then by considering schizotaxia, which, as it is currently formulated, is pre-prodromal and, therefore, less proximal. Finally, challenges to validation and future directions for research are considered.

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

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.

Are neurocognitive, clinical and social dysfunctions in schizotaxia reversible pharmacologically?: Results from the Changsha study

The Changsha study identifies adult, non-psychotic relatives of patients with schizophrenia who show deficits in neurocognitive, social, clinical and other dimensions, and who meet provisional criteria for a liability syndrome for schizophrenia ('schizotaxia'). In this study, we investigated whether negative symptoms, neurocognitive deficits, or other measures of clinical and social function in subjects who met our research criteria for schizotaxia were amenable to pharmacological remediation with a low dose (2.0 mg) of risperidone, a second generation antipsychotic medication. One hundred eighty nine relatives were assessed at the Mental Health Institute, Second Xiangya Hospital of Central South University, Changsha (Hunan Province, China), between 12/06 - 12/08. Eighty six of these individuals met modified criteria for schizotaxia, and 36 agreed to enter a 6-week, double-blind, placebo-controlled protocol. ANCOVAs using age and gender as covariates showed significant improvement in the risperidone group (n=20) on neurocognitive function (Wisconsin Card Sorting Test Total Errors and Perseverative Errors) and on a self-report measure of social function (Social Adjustment Scale), compared to the placebo-control group (n=16). Effect sizes were small to medium. Notably, risperidone effect sizes were larger (medium to large) in a subset of subjects (risperidone=15; placebo=10) whose membership in the schizotaxic group was supported empirically by cluster analysis. Negative symptoms did not change significantly in either analysis. The results are generally consistent with previous open-label investigations of risperidone administration in subjects with schizotaxia, and provide evidence that some neurocognitive and clinical problems are amenable to remediation in non-psychotic relatives of people with schizophrenia.

Leukemia inhibitory factor gene is associated with schizophrenia and working memory function

Leukemia inhibitory factor (LIF), a member of the interleukin-6 cytokine family, regulates the neuronal phenotype and coordinates astrocyte, oligodendrocyte, microglia, and inflammatory cell responses. The LIF gene is located on 22q12.1-q12.2, a hot spot for schizophrenia. Three polymorphisms of the LIF gene (rs929271, rs737812, and rs929273) were examined in a case-control association study of 390 patients with schizophrenia and 410 age- and sex-matched controls. Effects of a risk genotype of LIF on cognitive domains were evaluated by the Wechsler Adult Intelligence Scale-Revised, Wechsler Memory Scale-Revised, and Wisconsin Card Sorting Test (WCST) in 355 healthy volunteers. The LIF gene showed significant associations with schizophrenia at rs929271 and a haplotype consisting of rs929271-rs737812. After stratification by subtype of schizophrenia, the hebephrenic, but not paranoid, type was associated with the LIF gene at rs929271 (allele, P=0.014) and the haplotype (permutation P=0.013). Having the T-allele and T-carrier genotypes (TT and TG) of rs929271 were risks for hebephrenic schizophrenia, and the odds ratios were 1.38 (95% CI: 1.21-1.56) and 1.54 (95%CI: 1.19-1.98), respectively. Subjects with T-carrier genotypes made significantly more errors on the WCST compared with those without (P=0.04). The present study indicated that the LIF gene variant may produce susceptibility to hebephrenic schizophrenia and deterioration of working memory function.