Exploring Parameters of Driving Simulation in Relation to Drug Holidays in ADHD Patients (DS-ADHD1)

Attention deficit hyperactivity disorder (ADHD) or syndrome (ADHS) is a symptomatically defined condition that - if untreated - is linked to a significantly increased risk of traffic accidents. In a recent umbrella review, where data from reviews and meta-analyses on 21.142.129 adults was assessed, a pooled prevalence of 3.1% of ADHD in adults was estimated. Considering that globally around 1.35 million people lose their lives and more than 50 million are suffering from injuries or disabilities due to road accidents, the fraction of car accidents caused by ADHD as a risk factor is considerable and needs to be addressed. This risk is largely presumed to be caused by an elevated level of inattentiveness in affected persons.

Compounds of different groups, which can be classified in stimulants - formulations of methylphenidate and amphetamine - and non-stimulants - atomoxetin, guanfacine and clonidine -, have been shown to be effective in alleviating negative effects of ADHD, including inattentiveness. Under well-established but individually managed medication regimes, affected individuals can consequently lead a largely "unirritated" life and are not subject to fundamental restriction with respect to driving anymore.

In children and adolescents, documented negative effects of stimulant medication include loss of appetite and decreased growth rates. It could however be shown that short-term interruptions (weekend, school holidays, and alike), introduced to alleviate aforementioned effects, do not affect the drug's beneficial effects in functional use (e.g., school). Such monitored medication breaks are often called "drug holidays" (D). They have become standard procedure in well-monitored treatment, predominantly including behavioral therapy.

Based on own experience in childhood and or hearsay, also a fraction of affected adults under stimulant medication expresses the desire to take drug holidays and "be themselves" from time to time. With the predominant fraction of medication being fast acting drugs in extended-release formulation and typical patients being not only highly compliant but also extremely informed and adherent, these so-called "drug holidays" are reported an accepted in therapeutically accompanied settings of adults by now.

However, while the overall positive effect of stimulant treatment on driving performance has been confirmed in a row of excellent on road- and/or simulation studies using integrated driving scores (IDS), so far there is no study available addressing the effect of drug holidays in adult drivers on driving performance. This represents a significant gap of evidence for both medical experts and affected.

The proposed study will address this gap by exploring parameters of driving simulation in relation to drug holidays in ADHD patients.

Study Overview

• Status: Recruiting
• Conditions: ADHD; Driving Simulator Performance; Driving Behavior; ADHD - Attention Deficit Disorder With Hyperactivity; Driving Ability
• Intervention / Treatment: Drug: "drug holidays" (D)

• Study Type: Interventional
• Enrollment (Estimated): 26
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Stefan Lakämper, Dr. rer. nat.; Phone Number: +41793789984; Email: stefan.lakaemper@irm.uzh.ch
• Study Contact Backup: Name: Nan Li, MSc; Phone Number: +41797283245; Email: nan.li@irm.uzh.ch

Study Locations

• Switzerland
  • ZRH
    • Zurich, ZRH, Switzerland, 8050
      • Recruiting
      • Division of Traffic Medicine, Institute of Forensic Medicine, University of Zurich,
      • Contact: Stefan Lakämper, Dr. rer. nat.; Phone Number: +41793789984; Email: stefan.lakaemper@irm.uzh.ch
      • Contact: Nan Li, MSc; Email: nan.li@irm.uzh.ch

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion criteria:

• adult drivers
• ADHD-diagnosed, established ADHD-treatment only with stimulants
• known history of drug holidays based on own decision,
• at impaired eyesight with more than +/- 5 diopter or astigmatism
• contact lenses are required (for eye tracking)

Exclusion criteria:

• sensibility to motion sickness (kinetosis, dizziness etc. in 5 min screening drive)
• non-stimulant-treatment
• inability to understand the study procedure for linguistic or cognitive reasons
• professional drivers (if working during the study period)
• for women: pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1: M-M-D; stimulant-treated ADHD-affected participants will perform test sequence first in medicated state (M), then again in medicated state (M), then during "drug holidays" (D).	Drug: "drug holidays" (D); Participants omit three consecutive daily doses of ADHD-medication (stimulant).
Experimental: Group 2: M-D-M; stimulant-treated ADHD-affected participants will perform test sequence first in medicated state (M), then during "drug holidays" (D), then again in medicated state (M).	Drug: "drug holidays" (D); Participants omit three consecutive daily doses of ADHD-medication (stimulant).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Significant differences in IDS between conditions D and M	Primary outcome parameter IDS (Integrated Driving Score) will be calculated by summation of z-scores of typical driving parameters such as, for example, the standard deviation of lane position (SDLP), standard deviation of velocity (SDS) or number of inappropriate lane departures, ILD. IDS will be measured on day 0 (= baseline, Visit 1), on day x (with x≥4, Visit 2) and on day x+3 (Visit 3).	0, x, x+3 days, with x≥ 4 days

Collaborators and Investigators

• Sponsor: Stefan Lakämper
• Collaborators: Psychiatric University Hospital, Zurich; Swiss Federal Institute of Technology in Zurich (ETHZ)
• Investigators: Principal Investigator: Stefan Lakämper, Dr. rer. nat., University of Zurich; Principal Investigator: Kristina Keller, Dr. med., University of Zurich

Study record dates

Study Major Dates

• Study Start (Actual): June 2, 2025
• Primary Completion (Estimated): October 31, 2026
• Study Completion (Estimated): October 31, 2026

Study Registration Dates

• First Submitted: March 14, 2025
• First Submitted That Met QC Criteria: March 27, 2025
• First Posted (Actual): April 4, 2025

Study Record Updates

• Last Update Posted (Estimated): June 5, 2025
• Last Update Submitted That Met QC Criteria: June 2, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: driving simulation; eye tracking; driving performance; EEG-recording; stimulant treatment; drug holidays
• Additional Relevant MeSH Terms: Mental Disorders; Neurodevelopmental Disorders; Attention Deficit and Disruptive Behavior Disorders; Attention Deficit Disorder with Hyperactivity
• Other Study ID Numbers: DS-ADHD1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Results will be published in peer-reviewed journals. Anonymized raw data will be made available upon request.
• IPD Sharing Time Frame: starting after publication of study protcol and/or results
• IPD Sharing Access Criteria: upon request by mail
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No