Schizophrenia is a serious disease affecting 30,000+ New Zealanders and has a huge economic impact, estimated at $300M. The antipsychotic drugs used to treat schizophrenia cost NZ more than $61 million per year and are the second most costly class of drug (Pharmac 2009 review). However, these medications cause serious side effects similar to type 2 diabetes, contributing to the increased morbidity of these patients. Our recent research in animals has identified a mechanism by which these drugs affect blood sugar regulation and suggests the normal treatments for type 2 diabetes in NZ will not be effective in treating this. However, it suggests that new treatments targeting a hormone, GLP-1 (glucagon-like peptide-1), would be better. We propose a clinical trial to test whether this is the case in humans. This study not only has enormous potential to rapidly improve patient outcomes but also to improve the efficiency and cost-effectiveness of health delivery.