New and encouraging findings regarding the use of ketamine for depression in the context of psychotic symptoms have been published by Pennybaker et al. (1). In their analysis, patients with bipolar disorder without a history of psychosis had a more robust response to ketamine, and patients with a history of psychosis had a significant response compared with placebo as well. Concerning dissociative symptoms, even though patients with a history of psychosis endorsed more symptoms, these were not maintained after a 40-minute period, and no full psychosis was induced in their sample.
da Frota Ribeiro, C. M., Sanacora, G., & Ostroff, R. (2017). Reply to: Ketamine and Psychosis History: Antidepressant Efficacy and Psychotomimetic Effects Postinfusion. Biological Psychiatry. 10.1016/j.biopsych.2017.01.012