This study aims to evaluate the efficacies of an online mindfulness-based intervention for emerging adults with ADHD in Malaysia. The investigators hypothesized that online mindfulness-based intervention may improve ADHD symptoms and executive functions of emerging adults with ADHD.

Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder that often persist to adulthood. In Malaysia, the Chinese ethnic is having the highest prevalence rate of hyperactivity symptoms. Nevertheless, there are only limited evidence-based treatment options targeting the core symptoms of ADHD, as well as executive functions in adulthood. In addition, conventional psychotherapeutic approaches for adults with ADHD have found to be highly labor-intensive. Emerging adulthood is a distinct developmental stage of 18 - 29 years old, with unique challenges that rarely addressed in mental health system. Recently, mindfulness-based intervention appears to be a promising treatment for adults living with ADHD but it has not been evaluated among Malaysian emerging adults with ADHD. The investigators proposed a two-arm randomized controlled trial, comparing an eight-week online mindfulness-based intervention program with an online introductory psychology program. The outcomes include changes of inattention symptom, changes of hyperactivity-impulsivity symptom, and changes of executive functions from pretest to posttest, 1-month follow-up and 3-month follow-up. To investigators' best knowledge, this randomized controlled trial will be the first to test the efficacious of online mindfulness-based intervention for ADHD among emerging adults. It will provide evidence on the efficacious of online treatment for this often-overlooked population in the mental healthcare system.

Inclusion Criteria:

• 18 to 29 years old.
• Diagnosis of ADHD.
• Completed at least six years of Chinese education.
• Participants taking psychotropic prescriptions will be allowed to participate, if they prescriptions were stable for at least 6 weeks prior to their participation in this study.

Exclusion Criteria:

• History or current presence of substance dependence, psychotic illness, bipolar disorder, personality disorders, conduct disorder, chronic suicidal, or self-injurious behaviour as reported in the Diagnostic Interview For Anxiety, Mood, Obsessive-Compulsive and Related Neuropsychiatric Disorders (DIAMOND).
• Non-verbal intellectual ability of percentile ranks 25 or below.
• Received cognitive-behavioural therapy (CBT) for ADHD or any form of mindfulness-based intervention in the past 2 years.

All outcome measures data may be shared OSF Platform after the publications.

Data will be made available after December 2022.

Data collected from this study, including de-identified individual participant data, will be made available upon publication to members of the scientific and medical community for non-commercial use only, upon email request to the corresponding author. The study protocol, statistical analysis plan, and informed consent forms are available on ClinicalTrials.gov.