Study results presented at the 2014 APA annual meeting show patients treated with vortioxetine significant improvement in composite cognition scores compared to patients treated with placebo, independent of the drug's effect on their depression symptoms.
Vortioxetine (brand name: Brintellix), which was approved last October in the US for the treatment of major depressive disorders in adults, may also improve cognition independently of any effect on depression, according to a new study.
The results of a randomized, double-blind, placebo-controlled trial of vortioxetine inpatients with major depressive disorder were presented on May 5 at the American Psychiatric Association’s 2014 annual meeting in New York City, NY.
The eight-week trial, which ended last fall, enrolled 598 patients ages 18 to 65 with recurrent moderate to severe major depressive disorder. Approximately one-third received once-daily vortioxetine 20 mg and another third received vortioxetine 10 mg, both of which are standard dosages for the medication. The other third were given a placebo.
At the conclusion of the trial, cognitive function was assessed according to a standard composite z-score consisting of the DSST and RAVLT scores, which measure the four elements of cognition: executive function, learning and memory, processing speed, and attention. Patients’ self-assessments were also reported.
For both doses of vortioxetine, the participants showed significant improvement in cognition compared with the control group, according to Roger S. McIntyre, MD, a professor of psychiatry at the University of Toronto and the lead investigator of the trial. The mean treatment differences versus placebo were 0.36 for those on the lower dosage and 0.33 for those on 20 mg.
To put it another way, McIntyre said the trial participants who were given vortioxetine showed improvement ranging from 0.23, or “small,” to 0.52, or “medium.” By comparison, a random sample of patients with major depressive disorder would measure only 0.2 to 0.25, he said.
In terms of the drug’s main indication, treating depression, the trial also exhibited significant efficacy for vortioxetine, as expected. The mean MADRS score improved by 15.6 for patienst on the 10 mg dosage and by 17.6 for those on 20 mg, compared with 10.9 for those on placebo. Sizable differences versus the control population were also seen in CGI-S and CGI-I results.
But wouldn’t an improvement in cognitive function be expected as a standard result of taking antidepressants, as people became less depressed, felt better about themselves, and were better able to function?
“There is a ‘duh’ factor here,” McIntyre conceded.“The significance of our trial is that the benefit was independent” of the efficacy of the drug as an antidepressant.
“Even people whose depression did not get better, their cognition improved,” he added.
In other words, the positive results on the MADRS and CGI scores did not overlap one-for-one with the positive results from the DSST and RAVLT measurements. The people who improved on the cognition measurements were not necessarily identical to those who improved on the measurements of depression.
McIntyre said that this experiment was the first time that any antidepressant has been shown to achieve such an independent outcome in cognition.
The implications, both for individuals and for the larger community are important, McIntyre suggested. “It’s not sufficient to just improve someone’s depression. We know that’s rarely sufficient to get them back to work,” he explained. “But if they can improve their cognition, that gives them a better chance to work, and to become productive members of society.”