Ideally, patients taking Benzodiazepine and anti-depressants will be excluded because of the influence of these drugs on the cognitive test results and hippocampal volume. If it is deemed impractical to completely exclude these patients, all subjects will at least be tried to keep consistent with their antipsychotic dosages, by not permitting more than a 25% change in dose in the first 6 weeks after commencement of the intervention.