Investigating the Effect of Vortioxetine in Adult ADHD Patients

The purpose is to determine the effect of vortioxetine treatment on ADHD symptoms in adult patients with ADHD in a 12 weeks study.

The study employed the Sequential Parallel Comparison Design (SPCD), a clinical study design which intend to increase signal detection by using two stages of treatment:

* Stage 1 - first 6 weeks of the 12-weeks treatment period (Visit 2/Baseline 1 to Visit 5/Week 6)
* Stage 2 - last 6 weeks of the 12-weeks treatment period (Visit 5/Baseline 2 to Visit 8/Week 12)

In Stage 1, patients were randomized to placebo or vortioxetine 10 or 20mg. Patients on vortioxetine 10 or 20mg/day during Stage 1 remained on the same treatment in Stage 2. Responders to placebo in Stage 1 remained on Placebo in Stage 2. Patients who were placebo non-responders during Stage 1, defined as patients with a \<30% reduction in AISRS total score from Baseline 1, were re-randomized to placebo or vortioxetine 10 or 20mg/day in Stage 2.

Eligibility Criteria:
Inclusion Criteria:

* The patient is willing and able to attend study appointments within the specified time windows.
* The patient is an outpatient.
* The patient is diagnosed with a primary diagnosis of ADHD according to the DSM-5™ classification.
* The patient has an AISRS total score ≥24.
* The patient has a CGI-S rating ≥4 (moderately ill or worse).

Exclusion Criteria:

* The patient has previously been treated with vortioxetine.
* The patient has any current psychiatric disorder (DSM-IV-TR™ criteria), other than ADHD, as assessed using the Mini International Neuropsychiatric Interview (MINI).
* The patient has a known first-degree relative with bipolar disorder.
* The patient suffers from intellectual disability as evaluated by the Wechsler Abbreviated Scale of Intelligence (WASI) II vocabulary and matrix.
* The patient suffers from organic mental disorders, or mental disorders due to a general medical condition (DSM-5™ criteria).
* The patient has reported current use of, or has tested positive for, drugs of abuse (opiates, methadone, cocaine, amphetamines \[including ecstasy\], barbiturates, benzodiazepines, and cannabinoids). If a patient tests positive for opiates due to incidental use of codeine containing medication, as assessed in a clinical interview, the drug screen may be repeated up to three weeks later but the retest result must be available from the central laboratory latest at Visit 2 and has to be negative for this patient to be eligible for enrolment. If a patient tests positive for amphetamines due to his/her ADHD current treatment, as confirmed by a clinical interview, the patient is eligible for enrolment provided this treatment is discontinued two weeks prior to the Baseline Visit.
* The patient has a history of two prior failed (\<50% improvement in symptoms) adequate trials of ADHD treatment.
* The patient has any other disorder for which the treatment takes priority over treatment of ADHD or is likely to interfere with study treatment or impair treatment compliance.
* The patient has a history of moderate or severe head trauma or other neurological disorders or systemic medical diseases that are, in the investigator's opinion, likely to affect central nervous system functioning.
* The patient has attempted suicide within the last 6 months or is at significant risk of suicide (either in the opinion of the Investigator or defined as a "yes" to suicidal ideation questions 4 or 5 or answering "yes" to suicidal behaviour on the Columbia-Suicide Rating Scale (C-SSRS) within the last 12 months).

Other protocol defined inclusion and exclusion criteria do apply