Abstract
Objective:
To characterize the size and course of placebo response in attention-deficit/hyperactivity disorder (ADHD), with informant and moderator effects, and illustrate its importance by comparison to Multimodal Treatment Study of ADHD (MTA) 3-month data.
Methods:
In two randomized clinical trials parents and teachers rated DSM-IV ADHD symptoms (Sx) on pill placebo at baseline (BL), 8, 12, and 16 weeks for 57 children age 5–12 with ADHD (25 inattentive, 32 combined type) and on an intense 12-week nonmedical control condition (NMCC) for 27 children age 6–12.
Results:
Parent- and teacher-rated placebo effects peaked at 12 and 8 weeks, respectively. Changes from BL are significant (p = 0.001) by parent and teacher on inattentive Sx (d = .60, .56 for pill placebo; d = 1.48, .51 for NMCC) and on hyperactive/impulsive Sx by parent (d = 0.48 pill; d = 1.26 NMCC). Teacher-rated hyperactive/impulsive show greater placebo effect September–January than February–May (p = 0.017). Teacher-rated inattentive Sx shows a significant (p = 0.033) interaction of season*subtype. Compared to placebo data, MTA treatments show significant benefit (p = 0.000) at 3 months on both inattentive and HYP/IMP symptoms for medication management and combination groups but not for behavioral treatment (Beh) or community comparison groups, except for teacher-rated HYP/IMP for Beh (p = 0.002).
Conclusions:
Parent/teacher ratings show a medium placebo effect for pill placebo and a large effect (d > 1.2) by parent for intense, complex NMCC, suggesting that parent-rated placebo response depends on the complexity/intensity of the control condition. Raters agree on inattentive but diverge on HYP/IMP Sx. Teachers’ perceptions of HYP/IMP severity change by season. Pill placebo data indirectly support the 3-month efficacy of two MTA treatments, combination and medication management.
Get full access to this article
View all access options for this article.