Comparative Effectiveness Study of Two Forms of Ketamine for Treatment-resistant Depression
The goal of this study is to compare the effectiveness of two formulations of ketamine - Spravato® and racemic ketamine - in people with treatment-resistant depression (TRD). The main questions it aims to answer are:

How the two formulations compare in terms of their effectiveness in treating TRD.
How the two formulations compare in their acceptability to patients, safety, effects on patient quality of life and function, and cost effectiveness.

Participants will be randomised to receive either Spravato® or racemic ketamine treatment and asked to complete some questionnaires to assess the effects on mood, treatment acceptability, side effects, quality of life and function, and health economic outcomes.
- EligibilityCriteria: Inclusion Criteria:  Adult with treatment-resistant depression (TRD: not responded adequately to at least two different antidepressants of adequate dose and duration) who has a current depressive episode (DSM 5) Assessed and attested by clinic psychiatrist as appropriate to receive either racemic ketamine or Spravato® ketamine treatment for TRD Aged ≥18 years Written informed consent for research study obtained  Exclusion Criteria:  Not able to give informed consent Any physical or mental condition which, in the opinion of the investigator, could interfere with study participation including outcome assessments Patients who require an interpreter/translator for the clinic consent process, due to the infeasibility of obtaining an interpreter for research assessments, including self-rated scales - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult