Assessments of dissociation and other ASCs
dissociative amnesia, dissociative depersonalization, anxiety
To address our first objective to test whether specific aspects of dissociation and other altered states of consciousness differed across dose conditions, we utilized the CADSS and the 5D-ASC to assess specific aspects of ketamine-induced dissociation and other ASCs. CADSS is a 23-item clinician-administered questionnaire that was assessed pre- (We chose to assess blissful state, anxiety, and impaired control and cognition from the 5D-ASC to complement the CADSS, since these either directly assess an affective state or are likely to induce a particular affective state. Participants completed the 5D-ASC scale after scanning was complete and were instructed to rate retrospectively as if they were 20 min into the infusion. Building upon previous evidence of ASCs predicting treatment responses, in this report we included dissociative depersonalization, derealization, and a blissful state as ASCs that we hypothesized would relieve negative affective brain states or promote positive affective ones, while dissociative amnesia, anxiety, and impaired control and cognition were hypothesized to exacerbate negative affective brain states or dampen positive affective ones. In addition to the above quantitative assessments, we used keywords from the CADSS and 5D-ASC to prompt participants to describe their experience, and we recorded narratives for the last five participants (P09–P13).