HDAC Inhibitor Augmentation to Clozapine

The goal of this study is to perform a pilot clinical study with a small sample of subjects to evaluate the safety and tolerability of vorinostat when combined with clozapine treatment in patients with schizophrenia. The investigators will also evaluate the potential translation of our preclinical data into a clinical use of vorinostat for cognitive impairment in clozapine-treated schizophrenic patients. Potential participants will be receiving stables doses of clozapine for a minimum period of 6 months before entry into the study. Clozapine was selected because i) the majority of our studies in mouse models were performed after chronic treatment with this atypical antipsychotic, and ii) the investigators' data in postmortem human brain samples of subjects with antemortem diagnosis of schizophrenia suggest up-regulation of HDAC2 in frontal cortex of schizophrenic subjects treated with atypical, but not typical, antipsychotic drugs. The HDAC inhibitor vorinostat was selected because preliminary data suggest that chronic treatment with vorinostat improves HDAC2-dependent cognitive function in rodent models. Additionally, vorinostat is the first HDAC inhibitor approved by the U.S. Food and Drug Administration (FDA) for the treatment of cutaneous T-cell lymphoma. Dose(s) of vorinostat have been selected based on previous clinical studies in such patients with brain metastasis.