This study will evaluate if a specific treatment for emotion regulation in ADHD, GEARS, effectively reduces symptoms of emotional dysregulation. GEARS will be evaluated through a randomized controlled trial (RCT) and a qualitative interview study.

This project aims to investigate two main questions:

1. Is GEARS an effective treatment for emotion regulation difficulties in adult ADHD patients?
2. How do participants perceive the impact of completing the GEARS treatment? Study 1 investigates research question 1 through an RCT comparing GEARS to a passive control group. Data are collected using validated measures before and after treatment/waiting period, as well as at six and 12 months follow ups.

Sample size: 150 participants, ensuring sufficient statistical power to detect significant between-group differences, even with some attrition.

Study 2 examines the patients' perspectives on the treatment by interviewing 15-20 participants about their experience with GEARS. The interviews focus on GEARS' perceived impact. Interviews will be recorded, transcribed, and analyzed using thematic analysis to identify key recurring themes.

The trial will evaluate the GEARS manual. ADHD is one of the most common psychiatric diagnoses, with a growing demand for psychological treatment. Many adults seek help for impaired emotion regulation, yet evidence-based treatments are lacking. GEARS has shown promising results and addresses a critical need in psychiatric outpatient care. If proven effective in controlled studies, it could be widely implemented, enhancing functional outcomes in work and family life. Given the negative impact of emotion dysregulation, establishing evidence for this clinically developed and tested method is essential. Participants Inclusion criteria; (1) being diagnosed with ADHD according to DSM criteria, (2) age 18 years orabove, and (3) having identified problems with emotion regulation difficulties. Exclusion criteria: (1) diagnosis of intellectual disability, (2) diagnosis of autism (3) substance abuse, (4) severe mental illness (e.g., severe depression, anorexia) or comorbidity requiring clinical priority, (5) difficulties allocating time to participate due to social, academic or occupational circumstances hindering engagement in treatment, (6) other ongoing psychotherapy, and (7) difficulties accepting the group setting.

Treatment will take place within psychiatric outpatient clinics in regular care in Stockholm. Participants will be randomized to either start the intervention or to waitlist control. The GEARS is conducted in groups of around 8 participants led by two skilled therapist experienced in CBT and ADHD.

Inclusion criteria Treatment Method: GEARS is a new manual-based group treatment consisting of 14 weekly 2-hour sessions with eight participants and two group leaders. The group leaders, who are licensed psychologists or psychotherapists with CBT training and experience with this patient group, undergo training in the GEARS protocol prior to the start of treatment. The protocol is based on CBT with elements of DBT, ACT, and research on emotion theory and affect dysregulation in ADHD. The treatment is adapted to the needs of individuals with ADHD and designed to provide support so that executive difficulties do not become an obstacle to benefiting from the treatment.

In addition to the group sessions, each participant receives 30-60 minutes of coaching every other week with a group leader. The purpose is to support homework assignments, the application of treatment strategies in relation to individual challenges, and to strengthen the therapeutic process. Coaching sessions can take place on-site, via telephone, or via video.

The GEARS manual gives a clear agenda for the 14 group sessions and provides PowerPoint presentations, worksheets, and texts designed to increase understanding, acceptance, and regulation of emotions. The 14 sessions of the treatment are organized to cover the following themes:

Week 1: Introduction

Week 2: Mindfulness I + Acceptance

Week 3: Mindfulness II + The Normal Function of Emotions

Week 4: Mindfulness III + Emotional Awareness

Week 5: Primary and Secondary Emotions

Week 6: Self-reinforcement of Emotions / "Finished Behavior Analysis"

Week 7: Self-reinforcement of Emotions / "Finished Behavior Analysis"

Week 8: Impulse Control

Week 9: Emotional Control and Avoidance vs. Willingness and Acceptance

Week 10: Communication Skills

Week 11: Regulating Emotions Without Avoiding Them

Week 12: Valued Directions I + Relapse Prevention

Week 13: Valued Directions II

Week 14: Relapse Prevention / Termination

Measurements: Measures of emotion regulation and symptoms of ADHD, depression, anxiety and quality of life will be used to evaluate effects of treatment. Participants will be assessed pre, post and follow up at 6 and 12 months after treatment completion.

Inclusion Criteria:

• being diagnosed with ADHD according to DSM criteria,
• age 18 years or above, and
• having identified problems with emotion regulation difficulties.

Exclusion Criteria:

• diagnosis of intellectual disability,
• diagnosis of autism
• substance abuse,
• severe mental illness (e.g., severe depression, anorexia) or comorbidity requiring clinical priority,
• difficulties allocating time to participate due to social, academic or occupational circumstances hindering engagement in treatment,
• other ongoing psychotherapy, and
• difficulties accepting the group setting.