The goal of this clinical trial is to learn whether the ADHD&me (ADHD&ik) intervention can improve self-esteem in youth aged 16-25 years with Attention Deficit Hyperactivity Disorder (ADHD). The ADHD&me program is a cognitive behavioral therapy (CBT)-based intervention designed to help people with ADHD to develop a more positive view of themselves in their transition to adulthood.

The main questions it aims to answer are:

• Does the ADHD&me intervention improve self-esteem in youth with ADHD, and are these effects maintained over time?
• Does the intervention also improve related outcomes, such as masking of ADHD-related behaviors and co-occurring mental health symptoms including anxiety, depression, and stress?

In this RCT, participants are assigned either to immediate treatment or to a waitlist control condition, with the latter receiving the intervention after an eight-week delay.

Participants will:

• Take part in seven individual therapy sessions according to the ADHD&me intervention.
• Complete questionnaires about self-esteem, masking of ADHD-related behaviors, ADHD symptoms, and co-ccurring mental health symptoms at several time points.
• Complete short daily assessments (ecological momentary assessment) during one week at the start of the study and one week after the intervention or waitlist period to report momentary self-esteem, emotions, distress, and activities.

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition characterized by symptoms of inattention, impulsivity, and hyperactivity that may lead to impairments across multiple life domains. Although ADHD is often diagnosed in childhood, symptoms frequently persist into adulthood. Emerging adulthood is a developmental stage characterized by increasing independence and responsibilities related to education, work, and social relationships. For individuals with ADHD, these demands may intensify existing difficulties with attention regulation, organization, and time management. In addition to the core symptoms of ADHD, many individuals experience mental health difficulties such as anxiety, depression, and stress, which can further complicate daily functioning. These challenges highlight the importance of interventions that address not only ADHD symptoms but also broader psychological factors that influence functioning.

Low self-esteem is considered an important factor that may contribute to these difficulties. Throughout their lives, individuals with ADHD often encounter repeated experiences of failure, criticism, or negative feedback in academic, occupational, or social contexts. Over time, these experiences may lead to negative self-evaluations and reduced self-esteem. Low self-esteem may in turn exacerbate ADHD-related impairments and psychological distress, contributing to a negative cycle in which ADHD symptoms, stress, and comorbid mental health difficulties reinforce each other. Despite the importance of self-esteem for psychological functioning, many existing ADHD treatments primarily focus on reducing ADHD symptoms through skills training and may pay limited attention to self-esteem and masking. The aim of this study is therefore to evaluate whether the ADHD&me intervention improves self-esteem in emerging adults with ADHD and whether these effects are associated with changes in related psychological outcomes.

The ADHD&me (ADHD&ik) intervention was developed to address this gap by specifically targeting self-esteem in emerging adults with ADHD. The intervention consists of seven individual therapy sessions and aims to strengthen self-esteem by addressing negative self-evaluations and masking behavior and by supporting participants in developing a more adaptive relationship with their ADHD. A pilot study was conducted, and the intervention protocol was refined through an iterative process based on its findings.

The effectiveness of the ADHD&me intervention will be evaluated using a multicenter randomized controlled trial. Emerging adults with ADHD and low self-esteem will be randomly assigned in a 1:1 ratio to either (1) an immediate intervention group with two-month follow-up assessment or (2) a waitlist control condition receiving the intervention after an eight-week delay. Randomization will be performed using stratified block randomization based on ADHD medication use (yes/no), gender (male/female), and age group (16-20/21-25).

The primary outcome of the study is self-esteem. Secondary outcomes include masking of ADHD-related behaviors, ADHD symptoms, anxiety symptoms, depressive symptoms, perceived stress, executive functioning, rejection sensitivity, and quality of life. In addition to questionnaire assessments, ecological momentary assessment (EMA) will be used to examine fluctuations in self-esteem, emotions, and distress in daily life. Additional measures will assess treatment-related factors such as therapeutic alliance, client satisfaction, and treatment integrity to evaluate the quality of intervention delivery and therapists/participants' experiences.

Inclusion Criteria:

• 16-25 years old.

• Official ADHD diagnosis, that is confirmed by research team using the clinical interview MINI-S.

• Low self-esteem, determined through a structured and multi-step procedure to minimize subjectivity:

  • Referral by clinician. Clinicians from participating institutions identify potential participants. To ensure a uniform understanding of the study population and inclusion criteria, all clinicians receive specific training. The researcher(s) conduction the baseline assessment are also familiar with these training materials, so that the inclusion procedure is applied consistently.
  • Telephone screening. Two items from the Rosenberg Self-Esteem Scale (RSES; Rosenberg, 1965) are administered ("At times I think I am no good at all" and "All in all, I am inclined to think I am a failure"). A score of 3 (agree) or 4 (strongly agree) on either of these items is considered indicative of low self-esteem.
  • Baseline confirmation. During the baseline measurement, the full Rosenberg Self-Esteem Scale is administered. A cutoff score of < 15 is used as an objective reference point. This score is combined with a standardized clinical interview conducted by a trained researcher psychologist. At the ADHD section of the MINI-S at the baseline measurement, participants are asked by the researcher psychologist how their symptoms interfere with domains such as work, study, relationships, and self-esteem. If self-esteem is not mentioned, a follow-up question will be asked: "Many people with ADHD feel their symptoms affect their self-esteem, for example due to repeated negative feed- back, feeling like they are not good at things, or failing short. Do you recognize this in yourself"? Based on the participant's response, the trained researcher psychologist interviewer forms a professional, clinical impression of whether there are indicators of persistently low self-esteem (i.e.,insecurity, fear of failure, strong reactions to criticism, perfectionism, distress related to ADHD symptoms). This clinical assessment approach is based on examples provided by the Diagnostic Interview for ADHD in Adults (DIVA-2-NL; Kooij & Francken, 2010). In all doubtful cases, the inclusion decision will be discussed in consensus meetings with the research team and supervisor, ensuring high inter-rater reliability.

• Pharmacological treatment for ADHD is allowed, but medication dose should be stabilized for a minimum of 4 weeks at baseline measurement (T0). Although changes in ADHD medication during the study are not preferred, they may occur in practice. Any such changed will be carefully documented.

Exclusion Criteria:

• Concurrent psychopathology that requires immediate attention (e.g., severe depression, suicidal thoughts/risk of suicide (as determined by the referring therapist and/or research team). Other comorbidity is allowed.
• Undergoing any concurrent psychological treatment during the study, including any form of therapy for ADHD (e.g., CBT for planning skills). Psychoeducation completed prior to the study entry is allowed, but not during the study.
• Low self-esteem that directly stems from a traumatic experience, which would indicate the need for trauma-specific treatment. This will be determined by the referring therapist. If someone in addition suffers from low self-esteem due to the ADHD symptoms, an appropriate timing of each treatment will be dis- cussed by the referring therapist and potential client.
• IQ < 80 assessed with two WAIS-IV subscales (Wechsler, 2008): Vocabulary and Block Design.
• Severe substance use (as determined by the referring therapist and/or research team).
• Confirmed Autism Spectrum Disorder (ASD) diagnosis. This also applies when the referring therapist indicates that an ASD diagnosis is very likely, even if it has not yet been established. Since ASD diagnostic procedures are time-consuming and fall outside the scope of this research project, formal ASD assessment will not be conducted within this study.

Note. If included participants receive unforeseen supportive sessions outside the research setting, or if unforeseen medication changes occur during the study, these will be documented and considered during the analysis.

De-identified individual participant data (IPD) underlying the results reported in publications may be shared after completion of the PhD project and after publication of the (primary) study results. Data sharing will only take place with permission of the principal investigator and in accordance with participant consent, applicable privacy regulations (GDPR), and institutional data management policies. Data will be shared in coded form for scientific research purposes only and may require a data sharing agreement. Requests for access to the data can be submitted to the principal investigator.

Individual participant data and supporting materials will become available after publication of the (primary) study results and completion of the PhD project. Data will be available upon reasonable request for scientific research purposes, subject to approval by the principal investigator and in accordance with participant consent and applicable privacy regulations. Data will remain available for up to 15 years after completion of the study.

Access to de-identified individual participant data (IPD) and supporting information will be granted to researchers for scientific research purposes. Data will include the de-identified dataset underlying the results reported in publications, as well as the study protocol and statistical analysis plan.

Requests for access to the data can be submitted to the principal investigator. Data access will be granted after approval by the principal investigator and in accordance with participant consent, applicable privacy regulations (GDPR), and institutional data management policies. Data may be shared under a data sharing agreement.

Participants, therapists, and researchers are not blinded to treatment allocation due to the nature of the psychological intervention and the delayed treatment (waitlist) design. Randomization is conducted by an independent researcher who is not involved in treatment delivery or outcome assessments in order to minimize allocation bias.