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The present study examined the concurrent and predictive validity of the Allen Cognitive Levels (ACL) Assessment in a sample of 110 medicated patients with schizophrenia who received the ACL at discharge from a state psychiatric facility. Subsamples within this group of patients had received an Activities of Daily Living assessment (n = 64) and a comprehensive neuropsychological test battery (n = 48) at discharge, or a battery of community follow-up measures (n = 30) 1-3.5 years following discharge as part of other investigations. Positive correlations were found between the ACL and concurrent measures of adaptive and cognitive function. With respect to cognitive variables, stepwise multiple regression analysis revealed that the majority of the variance in ACL scores was predicted by neuropsychological test scores assessing higher level cognitive processes, such as visual organization, manipulation of information in working memory, and ability to inhibit a response to a prepotent stimulus. Finally, results revealed positive relationships between the ACL obtained at discharge and community functioning at follow-up. The results of this study provide some evidence for the concurrent and predictive validity of the ACL for patients with schizophrenia and suggest that further study of this assessment tool would be important to pursue in future investigations.

Previous studies have identified a putative gene locus for both schizophrenia and bipolar disorder in the chromosome 18q21 region. To identify candidate genes associated with these disorders we completed fine mapping analyses (using microsatellite markers) in 152 families from the Central Valley of Costa Rica (CVCR) (376 total subjects, 151 with a history of psychosis, 97 with a history of mania). Microsatellite analyses showed evidence of association at two contiguous markers, both located at the same genetic distance and spanning approximately 11 known genes. In a corollary gene expression study, one of these genes, malic enzyme 2 (ME2), showed levels of gene expression 5.6-fold lower in anterior cingulate tissue from post-mortem bipolar brains. Subsequent analysis of individual SNPs in strong linkage disequilibrium with the ME2 gene revealed one SNP and one haplotype associated with the phenotype of psychosis in the CVCR sample. ME2 interacts directly with the malate shuttle system, which has been shown to be altered in schizophrenia and bipolar disorder, and has roles in neuronal synthesis of glutamate and γ-amino butyric acid. The present study suggests that genetic variation in or near the ME2 gene is associated with both psychotic and manic disorders, including schizophrenia and bipolar disorder.