Researchers recently published two case reports that suggest that patients with a history of psychosis who also suffer from severe depression may benefit from receiving ketamine.
Psychosis is a severe mental disorder in which thought and emotions are so impaired that contact is lost with external reality.
Psychotics Usually Excluded
Traditionally, patients with psychotic disorders have been excluded from studies on the use of ketamine to treat depression because “some of the immediate effects of ketamine can actually mimic some of the symptoms of psychosis,” said Gerard Sanacora, MD, Ph.D., professor of psychiatry, Yale University.
But in a report (Medeiros da Frota Ribeiro, Sanacora, & Ostroff, 2017), Dr. Sanacora and colleagues describe “encouraging” long-term results in using ketamine to treat depression in patients with psychotic symptoms.
In these two patients, “we saw an antidepressant effect but not any worsening of perceptual or cognitive effects that could be related to psychosis,” said Dr. Sanacora.
Caution Still Needed
These case studies are consistent with another study (Pennybaker, Luckenbaugh, Park, Marquardt, & Zarate, 2017) that concluded, “clinicians should not assume that a single infusion of ketamine will exacerbate psychotic symptoms in predisposed patients.”
Nevertheless, until more data is gathered, Dr. Sanacora urged caution in using ketamine to treat patients with psychotic disorders.
“It’s not out of the question” to try ketamine in a patient with psychotic features “as long as there is safety criteria built in from the very beginning,” he told Medscape Medical News. “It really should only be used after more established treatments, including an atypical antipsychotic, or even probably ECT.”
“The population with major depression and psychotic features is a very difficult population to treat,” he added, “and if ketamine could have some benefit, that would be a very helpful.”