There are few efficacious pharmacological treatments for posttraumatic stress disorder (PTSD) and many patients fail to benefit from existing treatments. Vortioxetine, a recently developed antidepressant, acts as a serotonin modulator through inhibition of the serotonin transporter and actions at multiple types of serotonin receptors. Its unique pharmacodynamic profile suggests it may have efficacy for the treatment of PTSD.
We conducted a 12-week placebo-controlled, randomized clinical trial of vortioxetine (flexibly dosed from 10 to 20 mg/d) versus placebo in adults with PTSD. The primary outcome was change from baseline in the past-month version of the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), analyzed using a mixed-model repeated-measures analysis of variance.
Forty-one patients were randomized, and 32 (78%) completed the 12 weeks of treatment. The mean reduction in CAPS-5 scores at week 12 did not significantly differ between the 2 arms; the effect size for the difference in changes between vortioxetine and placebo on CAPS-5 total scores at week 12 was Cohen d = 0.29. However, at week 8, the drug-placebo difference was d = 0.78, which met the multivariate criteria for statistical significance, P = 0.014.
In this study of 41 patients, vortioxetine did not demonstrate superiority over placebo for adults with PTSD. Future PTSD trials may benefit from stratifying the randomization based on number of years since the index traumatic event and a history of failure to respond to treatment.