Lisdexamfetamine dimesylate in adults with attention-deficit/ hyperactivity disorder who report clinically significant impairment in executive function: results from a randomized, double-blind, placebo-controlled study

Abstract

Objective: Behavioral rating scales that assess impairments in executive function commonly associated with attention-deficit/hyperactivity disorder (ADHD) may offer advantages over neuropsychological testing. The primary objective of this study was to evaluate the efficacy of lisdexamfetamine dimesylate for executive function deficits in adults with ADHD and clinically significant executive function impairment using self-reported Behavior Rating Inventory of Executive Function-Adult version (BRIEF-A) assessments.

Method: This randomized double-blind study, conducted between May 2010 and November 2010, screened at least 1 participant at 35 of 39 registered US clinical research sites. Adults (aged 18-55 years) with a primary ADHD diagnosis (meeting full DSM-IV-TR criteria) and executive function deficits (assessed by baseline BRIEF-A Global Executive Composite [GEC] T-scores of at least 65) were randomized to treatment with optimized lisdexamfetamine dimesylate (30 mg/d, 50 mg/d, or 70 mg/d; n = 80) or placebo (n = 81) during a 10-week double-blind treatment period. Outcome measures included the BRIEF-A scales (GEC, index, and clinical subscales).

Results: At week 10 or at early termination, lisdexamfetamine dimesylate was associated with significantly greater reductions from baseline in mean BRIEF-A GEC T-scores than placebo (effect size, 0.74; P < .0001) and significantly greater reductions from baseline in mean T-scores for both BRIEF-A index scales (Behavioral Regulation Index and Metacognition Index) and all 9 clinical subscales (P ≤ .0056 for all). At week 10 or at early termination, mean T-scores for BRIEF-A indexes and clinical subscales were below levels of clinically significant executive function deficits (ie, < 65) with lisdexamfetamine dimesylate treatment. The mean (SD) GEC T-score was 57.2 (14.11) for the lisdexamfetamine dimesylate group and 68.3 (17.12) for the placebo group. The safety profile of lisdexamfetamine dimesylate was consistent with other long-acting psychostimulants.

Conclusion: Among adults with ADHD and clinically significant executive function deficits, lisdexamfetamine dimesylate was associated with significant improvements in self-reported executive function ratings.

Trial registration: ClinicalTrials.gov identifier: NCT01101022.