The goal of this naturalistic, open label, single arm intervention study is to investigate the effects of Esketamine in treating depression.The main aims to answer are:
* to investigate whether Esketamine is effective when added to ongoing antidepressant treatment
* to identify patient characteristics that will determine a therapeutic response to Esketamine in real-world practice
Participants will:
* attend the clinic for supervised self-administration of intranasal Esketamine treatment
* be observed for 2 hours following Esketamine administration including blood pressure monitoring
* be asked to complete a battery of questionnaires
* be reimbursed for travel expenses