Comparison of Ketamine Versus Saline During Sedation in Patients With Major Depressive Disorder: a Double-blind Trial

Summary

This open-label, randomized crossover study in healthy adults tests two propofol protocols to produce distinct experiential states. One induces brief loss of responsiveness with spontaneous emergence, intended to elicit dream reports; the other maintains light sedation without loss of responsiveness, intended to elicit non-dream experiences while participants remain responsive. The main goals are to (a) measure the protocol-concordant experiential report rate (how often each method produces its intended experience), (b) explore EEG correlates of these experiences in the two states, and (c) describe their phenomenology (what they are like). We will also examine short-term changes in well-being and sleep related to these experiences. Participants complete four sessions (two of each method) with EEG and routine monitoring, immediate post-session interviews, and brief questionnaires and daily sleep/dream logs before and after anesthesia sessions.

Eligibility

Age range

18–70 years

Sex

All

Healthy volunteers

Yes

Interventions

• Drug
  Propofol - Emergence-from-LOR Protocol

  Intravenous propofol infusion that meets the criteria: (1) maintenance of spontaneous ventilation, (2) sedation level corresponding to a Patient State Index (PSI) no lower than 25; and (3) loss of responsiveness (LOR) defined by the Richmond Agitation Sedation Scale (RASS) = -5 \[unarousable\]. Anesthesia is then maintained at that level for 30 minutes, followed by spontaneous emergence.

• Drug
  Propofol - Light Sedation Protocol

  Intravenous propofol infusion titrated stepwise to reach a state where participants are sedated but have behavioral responsiveness. Sedation is maintained at this level for 30 minutes.

Location