Statistical Tests of Significance
Analysis of variance (ANOVA) followed by Newman-Keuls tests and Students t tests were used to analyze the results of these studies. Statistical analyses were performed using Statistica for Windows (release 5.5, Statsoft Inc., Tulsa, OK) or SPSS for Windows (version 10, SPSS Inc., Chicago, IL).
Results and Discussion
The relative abundance of GAD67 in the dorsolateral prefrontal cortex is shown in Figure 4. Analysis revealed a significant increase in GAD67 expression in the schizophrenic cohort (F(2,35) = 4.12, p = 0.02; Newman-Keuls test, schizophrenia vs. normal-elderly, p = 0.023).
The schizophrenic cohort was significantly younger than the normal-elderly
group (Table 1). To determine whether age at death affected the differences
between groups, the schizophrenic and normal-elderly groups were subgrouped
into 2 groups of 10 subjects each that were matched for age to within
1 year of each other. Differences in the expression of GAD67 were reassessed
using t tests. The same significant (p < 0.02) group difference found
when analyzing the entire cohort was observed when comparing the groups
of schizophrenics and normal-elderly subjects that were matched for age
(Figure 4). Similar results were obtained when 2 subgroups of 10