The proposed study is to be carried out in 2021 - 2024 with youths aged 6 - 15 in Hong Kong. This is a randomized waitlist-controlled trial that aims to examine the effectiveness of the ADHD+ new service protocol. This ADHD+ new service protocol intervention will be delivered for 6 months in the format of groups by frontline social workers trained by professional clinicians including clinical psychologists and psychiatrists. It is designed to reduce ADHD and related symptoms in individuals aged between 6 and 15 years.

Core treatment components include internet use/addiction intervention, cognitive training, emotion management, social skills training, occupational training, emotion support/befriending, parenting training, and career guidance. It is hypothesized that youths receiving the intervention will have reduced ADHD and related symptoms when compared with controls.

Findings will allow the investigators to better understand the effectiveness of the new ADHD+ service; and in the long run, the service model can be generalized to community based early interventions for other uncomplicated mental disorders.

Inclusion Criteria:

• children, adolescent and young adults (Aged 6-15);
• have sufficient proficiency in Chinese to understand verbal instructions and give informed consent;
• clinically significant mild to moderate ADHD syndromes requiring intervention;
• without learning disabilities and intelligence quotient (IQ) score not lower than 70;
• are "more likely to commit time in the projects" for reasons such as intention to treat and
• receiving the New ADHD+ service.

Exclusion Criteria:

• known diagnosis of intellectual disability;
• not reaching syndrome diagnostic threshold for ADHD;
• already receiving medical interventions / treatments at Hospital Authority (HA) and/or private sector;
• known psychiatric diagnosis (stabilized diagnosis and treatment);
• current or active suicidal ideation or attempts;
• have received structured psychosocial intervention for more than 3 contact hours (for waitlist group); and
• refusal to give consent.