Community-Based Music Mindfulness Intervention on Children

The goal of this clinical trial is to learn how community-based music mindfulness interventions impact anxiety, depression, and overall emotional well-being in children and adolescents with attention-deficit/hyperactivity disorder and/or anxiety. The main questions it aims to answer are: * How do participants' psychological states change from the start to the end of the intervention? * What physiological changes, including heart rate variability and sleep patterns, are observed after the intervention? * Is this study feasible and acceptable to the community? Participants will: * Attend in-person sessions, bi-weekly for 8 weeks * Regularly complete psychometric assessments * Wear fitness trackers daily, including overnight, throughout the study period * Track self-guided intervention online * Participate in semi-structured interviews pre-/post-study

Inclusion Criteria: * Ages: 8-12 Exclusion Criteria: * Regular mindfulness or meditation practice (at least once/week) * Participation in formal meditation or mindfulness interventions within the past year * Suicidal ideation, self-injurious behaviour, or homicidal ideation * Active psychosis symptoms * Hospitalization within the past 6 months for psychiatric or medical conditions * Diagnosis of seizure disorder or other neurological disorders * History of thyroid or cardiovascular diseases * Current substance use disorders