Placebo Response and Its Predictors in Attention Deficit Hyperactivity Disorder: A Meta-Analysis and Comparison of Meta-Regression and MetaForest.
Int J Neuropsychopharmacol
; 25(1): 26-35, 2022 01 12.
Article
in En
| MEDLINE
| ID: mdl-34355753
ABSTRACT
BACKGROUND:
High placebo response in attention deficit hyperactivity disorder (ADHD) can reduce medication-placebo differences, jeopardizing the development of new medicines. This research aims to (1) determine placebo response in ADHD, (2) compare the accuracy of meta-regression and MetaForest in predicting placebo response, and (3) determine the covariates associated with placebo response.METHODS:
A systematic review with meta-analysis of randomized, placebo-controlled clinical trial investigating pharmacological interventions for ADHD was performed. Placebo response was defined as the change from baseline in ADHD symptom severity assessed according to the 18-item, clinician-rated, DSM-based rating scale. The effect of study design-, intervention-, and patient-related covariates in predicting placebo response was studied by means of meta-regression and MetaForest.RESULTS:
Ninety-four studies including 6614 patients randomized to placebo were analyzed. Overall, placebo response was -8.9 points, representing a 23.1% reduction in the severity of ADHD symptoms. Cross-validated accuracy metrics for meta-regression were R2 = 0.0012 and root mean squared error = 3.3219 for meta-regression and 0.0382 and 3.2599 for MetaForest. Placebo response among ADHD patients increased by 63% between 2001 and 2020 and was larger in the United States than in other regions of the world.CONCLUSIONS:
Strong placebo response was found in ADHD patients. Both meta-regression and MetaForest showed poor performance in predicting placebo response. ADHD symptom improvement with placebo has markedly increased over the last 2 decades and is greater in the United States than the rest of the world.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Attention Deficit Disorder with Hyperactivity
/
Placebo Effect
Type of study:
Clinical_trials
/
Prognostic_studies
/
Risk_factors_studies
/
Systematic_reviews
Limits:
Adolescent
/
Adult
/
Humans
/
Male
Country/Region as subject:
America do norte
Language:
En
Journal:
Int J Neuropsychopharmacol
Journal subject:
NEUROLOGIA
/
PSICOFARMACOLOGIA
Year:
2022
Document type:
Article
Affiliation country:
España