Nebulized Ketamine for the Treatment of Major Depressive Disorder

The objective of this study is to evaluate the effect of ketamine formalized to be dispensed via inhalation, as an adjunct to concomitant medications and therapies on those with moderate to severe depression currently in an inpatient psychiatric unit. Investigators will examine the effects of nebulized ketamine on depressive symptoms.

This is a prospective double-blind placebo controlled study in which an active placebo, Midazolam, will be used. Participants will commit to either 4 visits or 5 visits depending on which treatment arm they are randomized into. All visits can be done remotely, however, days in which the participant will be dosed will have to be in person. During dosing days, the participant will be monitored for a minimum of two hours. Study participant's vitals will be collected at regular intervals during the observation period.

Adult psychiatry inpatients who are 18 years and older with a diagnosis of moderate to severe depression will be screened for enrollment by the study.

Primary Outcome Measures

1. Change in depressive symptoms on the Montgomery-Åsberg Depression Rating Scale (MADRS)
   Montgomery-Asberg Depression Rating Scale (MADRS) has a range from 0 to 60, where the lower score indicates the better health status. Change in mean total Montgomery Asberg Depression Rating Scale (MADRS) score from the baseline (pre-dose day 1 ), Day 2 and last day of assessments (Day 8 or Day 10)

Secondary Outcome Measures

1. A change in depressive symptoms on the Montgomery-Åsberg Depression Rating Scale (MADRS) from the baseline (pre-dose on day 1) and 2 hours post-medication administration
   Montgomery-Asberg Depression Rating Scale (MADRS) has a range from 0 to 60, where the lower score indicates the better health status. Change in mean total MADRS prior to dose administration on Day 1, 2 hours after dose administration for each day.
2. Change in Beck Scale for Suicide Ideation
   Beck Scale for Suicide Ideation (SSI) has a range from 0 to 42, where the lower score indicates the better health status. SSI score of ≥4, response which would be defined as SSI ≥50% below baseline - 2 hours post medication administration and remission defined as SSI score of ≥50% and lower than 4 - 24 hrs after medication administration of follow-up
3. Clinician-Administered Dissociative States Scale (CADSS)
   Measurement of dissociative symptoms. Clinician Administered Dissociative States Scale (CADSS) comprises 23 subjective items, each on a 5 point scale, a "0" represents absence of any adverse events and "4" represents a severely bothersome side effect. A total score ranges from 0-92, a lower score indicates a better health status.
4. Side Effect Rating Scale for Dissociative Anesthetics (SERSDA)
   Overall side effects as measured by the Side Effect Rating Scale for Dissociative Anesthetics (SERSDA). SERSDA has 9 items, each graded on a five point scale, with "0" representing the absence of any adverse effects and "4" representing a severely bothersome side effect.
5. Maximal sedative effects using Modified Observer's Assessment of Alertness and Sedation ( MOAA/S)
   Modified Observer's Alertness/Sedation Scale ( MOAA/S) uses a 6 point scale. A "0" indicates failure to respond to painful stimulus, "5" represents fully alert. .
6. Richmond Agitation-Sedation Scale (RASS)
   Measurement of participant's consciousness with a rating ranging from +4 to -5. +4 represents "combative", +3 represents "Very agitated", +2 represents "Agitated" , +1 represents restless, 0 represents "Alert and calm", -1 represents "Drowsy", -2 represents "Light sedation", -3 represents "Moderate sedation", -4 represents "Deep sedation", and -5 represents "Unarousable".