Relative to comparison subjects without psychiatric history, cerebellar cortices from patients with schizophrenia contained significantly higher levels of GAP-43 (F=8.817, df=1, 24, p=0.007) and BDNF mRNAs (F=9.408, df=1, 24, p=0.005) (Figure 1). A similar finding was observed for GABAA-δ, although differences in the levels of this mRNA did not reach significance (F=3.323, df=1, 24, p<0.09). In contrast, the levels of the GABAA-α6 subunit mRNA in patients with schizophrenia were not significantly different from comparison subjects (F=0.013, df=1, 24, p=0.92). The observed differences remained significant when the three patients with schizophrenia who died by suicide were excluded from the analysis. No correlations were found between the levels of any of the mRNAs analyzed and postmortem interval, pH, or age, except for GAP-43, which showed a significant effect of brain pH (F=4.810, df=1, 24, p<0.04). In addition, a positive correlation was found between the levels of expression of the three activity-dependent genes across all samples (GAP-43 versus GABAA-δ subunit: r=0.58, p=0.0001; GAP-43 versus BDNF: r=0.37, p=0.04; and BDNF versus GABAA-δ subunit: r=0.54, p=0.002). In contrast, there was no correlation between activity-dependent and activity-independent gene expression (GAP-43 versus GABAA-α6: r=0.03, p=0.88; GABAA-δ subunit versus GABAA-α6 subunit: r=0.04, p=0.81; and BDNF versus GABAA-α6 subunit: r=0.17, p=0.40). Finally, we observed no differences in the levels of BDNF, GAP-43, GABAA-δ subunit, or GABAA-α6 subunit mRNAs between rats that were chronically treated with haloperidol and vehicle-treated animals.