Vortioxetine for attention deficit hyperactivity disorder in adults: A randomized, double-blind, placebo-controlled, proof-of-concept study

Background: Stimulants remain the mainstay of treatment for attention-deficit hyperactivity disorder (ADHD) but are often associated with insufficient response or poor tolerability, leading to many patients not wishing to be treated with controlled substances. Aims: This randomized, placebo-controlled, proof-of-concept study (NCT02327013) evaluated the efficacy of a multimodal antidepressant, vortioxetine, in the treatment of ADHD, using a two-stage sequential parallel comparison design. Methods: Patients aged 18–55 years with a diagnosis of ADHD (DSM-5) and a total score ⩾24 on the Adult ADHD Investigator Symptom Rating Scale (AISRS) were randomized in study stage I with a 1:1:3 ratio to six weeks of treatment with vortioxetine 10 or 20 mg/day, or placebo (n = 227). In study stage II, placebo non-responders (AISRS total score reduction