Synaptic Imaging and Network Activity in Treatment Resistant Depression

Inclusion Criteria: * Be male or female, aged between 18 and 55 years of age inclusive. * Have a diagnosis of MDD, Bipolar 1 or Bipolar 2 depression and fulfil criteria for TRD depression. TRD patients are defined as having inadequately responded to at least two courses of antidepressants, given in a therapeutic dose and duration (Fekadu et al., 2018). * Have moderate to severe depression symptoms as demonstrated by a MADRS score greater than 20. * Be physically healthy, defined as having no clinically relevant abnormalities identified by a detailed medical history and full examination including blood pressure and pulse rate measurement, 12-lead ECG and clinical laboratory tests * Have a good command of the English language. * Have no or very little knowledge of the Chinese language. * Provide a personally signed and dated informed consent document indicating that the participant has been informed of and agrees to comply with all aspects of the study. * Be willing and able to comply with scheduled visits, dosing plan, laboratory trials and any other necessary procedures. Exclusion Criteria: * Have a current diagnosed psychiatric disorder, except MDD, Bipolar 1 and Bipolar 2 disorders and comorbid generalised anxiety disorder (GAD), social anxiety and/or social phobia. * Have a current or previously diagnosed psychotic disorder: Schizophrenia, Schizoaffective Disorder, Delusional disorder, Schizophreniform disorder, Schizotypal (personality) disorder, or Brief psychotic dis…