 Participants will see a clinician at a pre-depletion screening visit that occurs maximum 7 days prior to commencing depletion. In addition the a physical examination and taking medical history, inclusionexclusion criteria will be verified, an ECG will be taken by a hospital cardiologist, and blood and urine samples will be collected for standard haematologyurinalysis, and a baseline assessment of amino acid and neurotransmitter levels. Patients would be maintained on their original dose of Quetiapine throughout the course of the study. 