Children with Down syndrome (DS) have a greater prevalence of Attention Deficit Hyperactivity Disorder (ADHD) than typically developing children. However, rates of stimulant medication treatment are disproportionately low in children with DS+ADHD, even though stimulants are the most efficacious ADHD treatment and are recommended by consensus guidelines for use in children with intellectual disability (ID) and comorbid ADHD. Possible reasons for this include: 1) difficulty accurately diagnosing ADHD in children with DS; 2) lack of safety and efficacy data regarding stimulant medication in children with DS+ADHD; and 3) concerns about cardiac safety, given the high incidence of congenital heart disease or defects (CHD) in the DS population.
The purpose of this research study is to test the safety and effectiveness of stimulant treatment in children with DS+ADHD. As part of the study, we will develop cardiac monitoring protocols that can be used by health providers prescribing stimulant medication to treat children with DS+ADHD.

What does participation involve?

The study consists of a Phenotyping Visit at the UC Davis MIND Institute where the participant will complete cognitive and behavioral assessments. Each child’s parent/caregiver will complete six parent-report forms and each child’s teacher/aide will be asked to complete five teacher-report forms online. Families can choose to only participate in the one-day phenotyping visit if desired.
For those children meeting criteria for ADHD and are interested in the clinical trial, there will be a medical screening that includes an Echocardiogram (ECHO) if not previously done, an Electrocardiogram (ECG), a collection of vital signs and a medical examination. Following the medical screening a three-night sleep study will be collected from home. If eligible to participate after these medical screening, the child will enroll in the clinical trial for a total of 30 weeks. There will be biweekly visits (estimated to take 40 minutes) for the first 14 weeks that include medical evaluations alongside parent-report forms and teacher-report forms obtained online. For the following four months, the child will be seen monthly for medical evaluations alongside parent-report forms and teacher-report forms obtained online. Telehealth visits can occur during weeks 2, 4, 6, 18, and 26.


  • Have a documented diagnosis of Down Syndrome
  • Ages 6-17 years old
  • English as primary language
  • Meet criteria for ADHD
  • No significant brain injury or psychosis/bipolar disorder medication

What else can I expect?

  • Comprehensive diagnostic assessment, including intelligence, behavioral and cognitive assessments. At the conclusion of the study, families will receive a psychological assessment report detailing those findings.
  • Methylphenidate, considered to be the most effective treatment for ADHD
  • A comprehensive cardiology evaluation
  • Up to $225 in gift cards for time spent participating in the study
  • There is no cost associated with study participation

Contact Us

If you have any questions regarding this study, please contact Danielle Ponzini at 916-703-0484

Principal Investigator:
Kathleen Angkustsiri, M.D., M.A.S.
Associate Professor of Clinical Pediatrics