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Proposal 1292

Title of the Proposed Research

Applications of Item Response Theory to Clinical ADHD Research: Analysis of the ADHDRS-IV and Modeling Response to Treatments and Item-Level Treatment Sensitivity

Lead Researcher

Alex Sturm


University of California, Los Angeles

Funding Source


Potential Conflicts of Interest

Potential conflicts of interest will be disclosed when the research is presented and published

Data Sharing Agreement Date

14 August 2015

Lay Summary

Attention-deficit/hyperactivity disorder (ADHD) is an externalizing behavioral disorder that affects between 5 and 10 percent of children and adolescents. A number of rating scales exist for the purpose of measuring symptoms of ADHD for children and adolescence including the CPRS, SNAP-IV, and the ADHDRS-IV. Rating scales serve as a necessary tool for clinicians who wish to determine presence and severity of ADHD symptoms, in addition to monitoring response to treatment. Because the best method for detecting the effectiveness of a treatment is through perceived changes in symptoms, accurate measurement of symptomatology is essential. However, as advances in quantitative methodology have improved measurement in domains such as physical functioning, emotional distress, and pain, clinical research in ADHD has lagged behind.

Item response theory (IRT), a latent variable model, presents an opportunity to improve the way we measure baseline clinical symptoms of ADHD and treatment response. The National Institutes of Health and the Patient-Reported Outcomes Measurement Information System (PROMIS) Cooperative Group have already taken advantage of the benefits of IRT to produce improved scales for a number of health conditions. To maximize the potential of IRT application in ADHD measurement, we must also capitalize on the increasing availability of data previously collected by investigators and companies that have a stake in the advancement of research and treatment.

Beyond improving scales, the effect of treatment and item-level treatment sensitivity can also be modeled in an IRT framework. “Which treatments work and for whom?” is a question that can be answered using IRT and is the central aim of this proposal. But, latent variable models such as IRT with many model parameters require big samples for stable and precise estimation. The last few years are making it increasingly possible to take advantage of the availability of data. Now, many samples exist and can be combined to both improve our measurement and understanding of symptoms and to identify targeted treatment approaches.

This proposal will be presented in two parts. Study 1 will use IRT to evaluate the psychometric properties of the ADHDRS-IV in a large, combined baseline sample of children and adolescents. Study 2 will model change in ADHD symptoms as a function of treatment within the IRT framework in order to examine item-level treatment sensitivity across several pharmacotherapies used to treat ADHD.

The results of this IRT analysis are predicted to identify a more concise and presumably more sensitive change index which could have research and clinical value both in diagnosis and in treatment assessment. Results will be submitted for publication in psychological methods journals.

Study Data Provided

Study LILLY-B4Z-US-LYBP: A Randomized, Double-Blind, Placebo-Controlled Study of Atomoxetine Hydrochloride in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder and Comorbid Anxiety
Study LILLY-B4Z-US-LYCC: Evaluation of Continuous Symptom Treatment of ADHD: A Placebo-Controlled Double-Blind Assessment of Morning-Dosed or Evening-Dosed Strattera
Study LILLY-B4Z-MC-HFBD: A Randomized, Double-Blind Study of Tomoxetine Hydrochloride, Methylphenidate Hydrochloride, and Placebo in Pediatric Outpatients with Attention Deficit/Hyperactivity Disorder
Study LILLY-B4Z-MC-HFBK: A Randomized, Double-Blind Study of Tomoxetine Hydrochloride, Methylphenidate Hydrochloride, and Placebo in Pediatric Outpatients with Attention-Deficit/Hyperactivity Disorder
Study LILLY-B4Z-MC-LYAC: A Phase 3 Randomized, Double-Blind, Placebo-Controlled Efficacy and Safety Comparison of Fixed-Dose Ranges (mg/kg/day) of Tomoxetine with Placebo in Child and Adolescent Outpatients with ADHD, Aged 8 to 18 Years
Study LILLY-B4Z-MC-LYAQ: Safety and Efficacy of Atomoxetine or Atomoxetine Plus Fluoxetine in the Treatment of Mixed Attentional and Affective Disorders
Study LILLY-B4Z-MC-LYAS: A Randomized, Double-Blind Study of Tomoxetine Hydrochloride and Placebo in Pediatric Outpatients with Attention Deficit/Hyperactivity Disorder and Comorbid Tic Disorders
Study LILLY-B4Z-MC-LYAT: Efficacy, Tolerability, and Safety of Once-Daily Atomoxetine Hydrochloride versus Placebo in Children with Attention-Deficit/Hyperactivity Disorder

Statistical Analysis Plan

Publication Citation

Sturm, A., McCracken, J. T., & Cai, L. (2017). Evaluating the Hierarchical Structure of ADHD Symptoms and Invariance Across Age and Gender. Assessment. 2017 Jun 1:1073191117714559. doi: 10.1177/1073191117714559.