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Study on How Methylphenidate Works in Adults with ADHD, Comparing Those with and Without Obesity

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the effects of a medication called Ritalin in adults with Attention Deficit Hyperactivity Disorder (ADHD). ADHD is a condition that affects attention, activity levels, and impulsivity, and it can have a significant impact on daily life. The study is particularly interested in comparing how the body processes Ritalin in adults with ADHD who are also living with obesity, compared to those with ADHD who are not obese.

The purpose of the study is to understand how Ritalin and its active component, known as alpha-phenyl 2-piperidine acid, behave in the body over time. Participants will be given Ritalin in the form of a prolonged-release capsule, which means the medication is released slowly into the body. The study will involve taking blood samples at various times after taking the medication to measure how much of the drug and its active component are present in the bloodstream. This will help researchers see if there are differences between those with and without obesity.

Throughout the study, participants will also be asked about how effective they feel Ritalin is in managing their ADHD symptoms, such as attention and hyperactivity. This feedback will be collected using a simple scale. The study will also gather some basic information about participants, like age, weight, and lifestyle habits, to help understand the results better. The study is expected to continue until March 2026.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, ensure that all necessary documents are signed, including the written consent form. This confirms understanding and agreement to participate in the trial.

  2. Step 2

    Medication administration

    The medication used in this trial is Ritaline L.P. 10 mg, which is a prolonged-release capsule taken orally. The dosage is stable and has been maintained for at least two weeks prior to the trial.

    Continue taking the medication as prescribed by the healthcare provider. The frequency and duration of administration remain consistent with prior instructions.

  3. Step 3

    Blood sample collection

    Blood samples will be collected at various times to measure the concentration of the medication and its active metabolite in the bloodstream. These times are: immediately before taking the medication (T0), 30 minutes after (T30 minutes), 1 hour after (T1 hour), 2 hours after (T2 hours), 3 hours after (T3 hours), 4 hours after (T4 hours), 7 hours after (T7 hours), and 8 hours after (T8 hours).

  4. Step 4

    Symptom assessment

    At each blood sample collection time, assess the effectiveness of the medication on attentional symptoms and hyperactivity/impulsivity symptoms using a visual analog scale. This scale ranges from 1 to 7, with higher scores indicating greater perceived effectiveness.

  5. Step 5

    Data collection

    Provide sociodemographic, medical, and biological data, including age, sex, weight, height, tobacco and alcohol consumption, and morning breakfast intake. This information is used for pharmacokinetic modeling.

    Additional assessments include creatinine levels for kidney function, blood count, liver function tests, and initial severity of ADHD symptoms using the Adult ADHD Self-Report Scale.

  6. Step 6

    Psychological assessment

    Complete baseline assessments of emotional regulation, impulsivity, and eating behaviors using standardized questionnaires. These assessments help understand individual psychological characteristics.

Who can join the trial?

6 criteria

  • Age must be 18 years or older.
  • Must have a diagnosis of ADHD (Attention Deficit Hyperactivity Disorder) confirmed by a doctor. This can be the mixed form, predominantly inattentive, or predominantly hyperactive/impulsive type.
  • Currently taking Ritalin LP (a medication for ADHD) with a stable dose for at least two weeks.
  • For the group with obesity: Body Mass Index (BMI) must be 30 or higher. For the group without obesity: BMI must be less than 30. BMI is a measure that uses your height and weight to work out if your weight is healthy.
  • Must be affiliated with a social security scheme.
  • Must provide written consent by signing a consent form.

Who cannot join the trial?

4 criteria

  • Patients who are not diagnosed with Attention Deficit Disorder with or without Hyperactivity (ADHD) cannot participate.
  • Patients who are not within the age range specified for the study cannot participate.
  • Patients who are part of a vulnerable population, which means they might need special protection, cannot participate.
  • Patients who do not meet the specific health conditions required for the study cannot participate.
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Investigated drugs

Methylphenidate is a medication used to help people with Attention Deficit Hyperactivity Disorder (ADHD). It works by changing the amounts of certain natural substances in the brain. This helps improve attention, focus, and self-control in people with ADHD. In this clinical trial, researchers are studying how the body processes this medication in adults with ADHD, comparing those who are obese with those who are not.

What is already known about the treatment

Methylphenidate – Methylphenidate is a medication commonly administered orally in the form of tablets or capsules. It is widely recognized in medical literature as a treatment for Attention Deficit Hyperactivity Disorder (ADHD), a condition marked by symptoms of inattention, hyperactivity, and impulsivity. The drug works by increasing the levels of certain chemicals in the brain, which helps improve attention and focus while reducing impulsive behavior. Methylphenidate is classified as a central nervous system stimulant and is often prescribed to both children and adults diagnosed with ADHD.

Investigated diseases

Attention Deficit Hyperactivity Disorder (ADHD) – Attention Deficit Hyperactivity Disorder is a neurodevelopmental disorder that begins in childhood, typically before the age of 12. It is characterized by symptoms of inattention, such as difficulty sustaining focus, and/or hyperactivity-impulsivity, which may include excessive fidgeting or an inability to remain still. These symptoms can significantly impact personal, social, academic, and occupational functioning. The disorder affects approximately 5% of children and adolescents and 2.6% of adults. Symptoms may vary in intensity and can persist into adulthood, affecting daily life and activities.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-519461-22-00Protocol codeDR240305Estimated enrolment30 patientsSponsorCentre Hospitalier Regional Universitaire De Tours

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