ABSTRACT: Sleep problems are common in adults with attention-deficit/hyperactivity disorder (ADHD). This analysis aimed to evaluate the impact of lisdexamfetamine dimesylate (LDX) on sleep quality in adults with ADHD.This 4-week, phase 3, double-blind, forced-dose escalation study of adults aged 18 to 55 years with ADHD randomized participants to receive placebo (n = 62), or 30 (n = 119), 50 (n = 117), or 70 (n = 122) mg/d LDX, taken once a day in the morning. The self-rated Pittsburgh Sleep Quality Index (PSQI) was administered at baseline and at week 4 to assess sleep quality. The PSQI global score assesses 7 sleep components (subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medications, and daytime dysfunction) each scored from 0 (no difficulty) to 3 (severe difficulty).The mean baseline PSQI global score was 5.8 for LDX and 6.3 for placebo (P = .19) indicating poor overall sleep quality. At endpoint, least squares (LS) mean change from baseline was -0.8 for LDX vs -0.5 for placebo (P = .33). The daytime functioning component showed significant improvement in LS mean change at endpoint for LDX compared with placebo (LDX -0.4 vs placebo 0.0, P = .0001). LS mean changes for the other 6 PSQI components did not significantly differ from placebo. Sleep-related treatment-emergent adverse events with an incidence >/=2% in the active treatment and placebo groups, respectively, were insomnia (19.3% and 4.8%), initial insomnia (5.0% and 3.2%), middle insomnia (3.6% and 0%), sleep disorder (0.6% and 3.2%), somnolence (0.3% and 3.2%), and fatigue (4.7% and 4.8%), and were generally mild or moderate in severity.For most subjects, LDX was not associated with an overall worsening of sleep quality and significantly improved daytime functioning in adults with ADHD.clinicaltrials.gov Identifier: NCT00334880.