Secondary objectives of this multinational study in children and adolescents with ADHD were to assess the long-term maintenance of effectiveness of LDX in improving health-related quality of life and reducing functional impairment , as gauged using the Child Health and Illness Profile-Child Edition : Parent Report Form ( CHIP-CE : PRF ) and the Weiss Functional Impairment Rating Scale-Parent Report ( WFIRS-P ) , respectively .