Effect of Methylphenidate versus Placebo on Attachment‑Related Learning in Children with Attention‑Deficit/Hyperactivity Disorder (ADHD)

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What is this study about?

The study focuses on children with Attention-Deficit/Hyperactivity Disorder, a condition that makes it hard to pay attention, sit still, and control impulses. The medication being tested is methylphenidate, a common pill that helps improve focus by increasing levels of a brain chemical called dopamine, which is involved in motivation and learning.

The purpose of the study is to investigate how methylphenidate influences attachment-related learning processes and behavior in children with ADHD. Participants will be randomly assigned to receive either the active medication or a look‑alike inactive tablet (placebo) for a short period. During the study, children will visit the clinic a few times for simple activities that involve interacting with a caregiver and answering easy questions.

Researchers will observe how children respond to cues from their caregiver compared with neutral cues, how they seek support, and how they express trust. These observations help understand the child’s attachment style and how the medication may affect everyday relationships. All procedures are designed to be brief, safe, and child‑friendly.

1 enrollment

you are added to the study after giving consent. at this point you will receive information about the study procedures and your responsibilities.

2 baseline assessment

initial assessments are performed to record your current symptoms, behavior, and any relevant medical information. these may include questionnaires, interviews, and simple tasks designed to measure attention and learning.

3 randomization

based on a computer-generated system you are assigned to receive either the active medication or a placebo tablet. the assignment is unknown to you and the study staff to keep the trial unbiased.

4 start of medication

you begin taking a tablet by mouth (oral route). the study medication contains methylphenidate hydrochloride, a stimulant commonly used to treat attention‑deficit/hyperactivity disorder (adhd). the prescribed dose is 60 mg per day, divided as instructed by the study protocol. the medication is taken for the entire study period, which may last up to three years (from october 2026 to september 2029). if you were assigned to the placebo group, you will take an identical‑looking tablet that does not contain active drug.

5 regular study visits

throughout the trial you attend scheduled visits. during each visit you complete follow‑up assessments, report any side effects, and have your medication use checked. the frequency of visits follows the study schedule provided by the research team.

6 final assessment

at the end of the study you undergo a comprehensive set of assessments similar to the baseline. these evaluate changes in attention, learning, and attachment‑related behavior.

7 study completion

after the final assessment you are thanked for your participation. any study materials you received are returned, and you receive a summary of the overall study findings.

Who Can Join the Study?

  • You (or your legal guardian) must sign a written form showing you agree to take part in the study, known as informed consent.
  • You must be between 8 and 12 years old and currently attend elementary school.
  • You must already have a diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD) that was confirmed by a doctor using a standard interview called K‑SADS, which is a structured set of questions to check ADHD symptoms.
  • You must have started medication with methylphenidate (MPH) within the past year and completed a 5‑week double‑blind, placebo‑controlled titration (a careful process where the dose is increased while neither you nor the doctor knows if the pill is the real medicine or a harmless sugar pill). During that time you were identified as a responder and an optimal dose of short‑acting MPH was set. Any later changes in dose or switching to a long‑acting form are allowed.
  • You and your primary caregiver must be able to speak and understand Dutch.

Who Cannot Join the Study?

  • Having a confirmed diagnosis of autism spectrum disorder (a condition that affects communication and social interaction) or a major neurological disorder such as epilepsy, because these conditions can change how children learn about relationships.
  • Currently taking any brain‑affecting medicines that are not stimulants (for example, atomoxetine, antidepressants, antipsychotics, guanfacine, bupropion), except melatonin. These are called non‑stimulant psychopharmacological treatments and could interfere with the study’s comparison.
  • Having used a stimulant medication (like Ritalin or Equasym) within the 32 hours before a testing visit. Stimulant medications are drugs that increase brain activity, and the study requires a break of at least 32 hours before each test.
  • Being involved in any family therapy, mediation, or parenting program at the time of either testing session. These are counseling or training programs for families that could affect the child’s behavior during the study.
  • Taking part in another research study that is testing a new drug or medical device (called an interventional trial with an investigational medicinal product or IMP).
  • Having an IQ score below 70, as measured previously with a standard children’s intelligence test (WISC‑V‑NL). An IQ below 70 indicates significant learning difficulties.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name City Country Status
Katholieke Universiteit te Leuven Leuven Belgium

Other Sites

No sites found in this category

Want to learn more about this study or check if you can participate? Contact us.

Trial status

Country Status Recruitment Start
Belgium Belgium
Not yet recruiting
01.10.2026

Trial locations

methylphenidate is a medication taken by mouth in tablet form. It is a stimulant that is commonly used to treat attention‑deficit/hyperactivity disorder (ADHD). In this study, the tablets are given to children with ADHD to see whether the medicine can change the way they learn about and respond to emotional connections with others. Researchers are looking to find out if the drug helps improve attachment‑related learning and behavior compared with not taking the active medication.

Attention-Deficit/Hyperactivity Disorder (ADHD) – Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental condition that begins in childhood and is marked by ongoing patterns of inattention, hyperactivity, and impulsivity. Children with ADHD often have trouble staying focused on tasks, may act without thinking, and tend to be unusually active for their age. These behaviors can affect school performance, relationships with peers, and family interactions. As the child grows, hyperactivity may lessen while difficulties with organization and attention often continue into adolescence and adulthood. The core features remain present over time, though their expression can vary as the individual matures.

Trial ID:
2025-525122-35-00
Protocol code:
S71588
Trial Phase:
Therapeutic confirmatory (Phase III)

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