Effectiveness of methylphenidate in adults with phenylketonuria and attention-deficit/hyperactivity disorder: An N-of-1 series

Conditions: Phenylketonuria
ADHD

Registration Number: NL-OMON24320

Lead Sponsor: Amsterdam UMC / Amsterdam Public Health (Personalized Medicine)

Brief Summary: /A

Detailed Description: Not available

Recruitment & Eligibility

Status: Pending

Sex: Not specified

Target Recruitment: 5

Inclusion Criteria

Minimum age of 18 years.
- On or off Phe-restricted diet.
- A definite diagnosis of classical PKU according to well-established guidelines.
- Meet DSM-5 criteria for ADHD and diagnosed with ADHD by an expert multidisciplinary team consisting of an ID physician, a psychologist, and a psychiatrist.
- Suffering from ADHD symptoms for which a dietary intervention would not suffice to improve behavioural problems.
- Presence of a patient’s caregiver for proxy-reports.

Exclusion Criteria

- Unable to take and/or send in dried blood spots.
- Unable to obtain informed consent from legal representative.
- Presence of ADHD in first- and second-degree relatives.
- Presence of a contra-indication for treatment with methylphenidate (e.g. cardiovascular disease).
- Planned surgery and/or general anaesthesia during the trial.
- Pregnancy.
- Breastfeeding (females).
- During treatment with non-selective, irreversible monoamine oxidase (MAO) inhibitors, or within a minimum of one month of discontinuing those drugs.
- Current treatment with acetazolamide, thiazide-diuretic and sodium bicarbonate, or sympathicomimetics.
- Current substance or alcohol abuse.
- Unable to swallow tablets / capsules.

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
The primary outcome measure is Goal Attainment Scaling.

Secondary Outcome Measures

Name	Time	Method
Secondary outcome measures are: <br>1) the Strengths and Difficulties Questionnaire (SDQ) - subschale hyperactivity/inattention<br>2) Emotion Dysregulation Inventory (EDI)<br>3) the Personal Questionnaire (PQ) to identify the three most obstructive symptoms experienced by participants<br>4) serum phenylalanine levels<br>5) adverse effects of methylphenidate.