['depression']
['ketamine', 'midazolam']

        Inclusion Criteria:

          -  Patients ≥18 years with unipolar major depressive disorder (DSM-IV)

          -  24-item Hamilton Rating Scale for Depression (HRSD-24) score of ≥21

          -  Referred for ECT

        For the randomised Phase 2, patients must have

          -  received a substantial course of ECT in Phase 1 (i.e. at least five sessions)

          -  achieved at least response criteria (i.e. ≥60% decrease from baseline HRSD-24 score
             and score ≤16 on two consecutive weekly ratings)

          -  have a nominated adult who can stay with them for 24-hours on out-patient treatment
             days

          -  Mini-Mental State Examination (MMSE) score of ≥24

          -  able to provide informed consent

        Exclusion Criteria:

          -  Any condition rendering patient medically unfit for ECT; general anaesthesia, ketamine
             or midazolam - assessed by physical examination, routine haematology and biochemistry
             investigations prior to enrolment in Phase I (routine care)

          -  Active suicidal intention

          -  Dementia, intellectual disability, or MMSE <24

          -  Lifetime history of bipolar affective disorder

          -  Current history of post-traumatic stress disorder

          -  Other Axis I diagnosis (DSM-IV)

          -  ECT in the six months prior to recruitment

          -  Alcohol dependence or substance misuse in the six months prior to recruitment

          -  Pregnancy or breast-feeding

          -  Residing in a nursing home

          -  Prisoner

          -  Diagnosis of terminal illness

          -  Inability or refusal to provide valid informed consent
      