Parents face day-to-day stress related to parenting and other stressors, such as low household income, child behavioural problems and high expectations for their children. Mindful parenting research is becoming popular in recent years, and substantial evidence supports the effect of mindfulness practices on improving health outcomes. The simplicity of Zentangle gives it the potential to cultivate and apply mindfulness practice in daily family life. Zentangle art is becoming popular in Hong Kong and in other countries and regions. However, there are limited exploratory trials to evaluate the effectiveness of Zentangle. Therefore, the aim of the present study is to assess the effectiveness of mindfulness-based Zentangle interventions for reducing depression and anxiety symptoms in parents with mild to moderate depression or anxiety.

A pilot randomised controlled trial (1:1 allocation ratio) on parents who have mild to severe depression or anxiety symptoms will be conducted. Participants will be approached through public posters or active approach in community centres, such as Caritas Community Centre. Interested individuals will scan the QR code on the poster and complete a short online questionnaire via Qualtrics. The research staff will contact the eligible respondents and send them a link for collecting the baseline questionnaire (T1). Randomisation will be conducted after obtaining consent and completion of T1. Participants will be randomised into the intervention or control groups using random numbers generated by a statistician not involved in any part of the study. The random numbers will be generated by Microsoft Excel. The recruitment staff will be concealed from the allocation process. The intervention group will receive two weekly sessions of training and complete the immediate post-intervention assessment (T2, two weeks after T1), and the 3-month assessment (T3, three months after T1). The waitlist control group will complete the assessments during the same time points and receive the training after completion of T3.

A Certified Zentangle Teacher (CZT) will deliver two 2-hour weekly group sessions to the intervention group. The content will include 1) an introduction to Zentangle, guide participants to set intentions of mindfulness, open mind, gratitude, and appreciation; 2) simple mindfulness practice in each session to cultivate mindfulness, such as body scan and sitting meditation; 3) step-by-step explanation and demonstration of examples of various patterns; 4) instruct participants to create their unique art; 5) interactive sharing of participants' artworks, experience and feelings during the workshop. After completing the assessments, the waitlist control group will receive the same training sessions. An art show will be organised afterwards. Parents will be invited to create one or two pieces of Zentangle artwork at home and submit them to the research team before the show.

The baseline characteristics of the two groups will be compared using an independent t-test and Chi-squared test. An intention-to-treat approach will be used and a multilevel mixed model will be built to calculate between-group mean differences in the outcomes after adjusting for the baseline values of the respective outcomes. The effect size (Cohen's d) will be calculated. Subgroup analyses will also be conducted based on the number of drawings actually performed by participants. Within-group mean differences will be compared by paired t-tests. Missing data were recognised as randomly missing and dealt with the multiple imputation method. A complete case analyses will performed as a sensitivity analysis. It is expected that the intervention group show more significant improvements in the measured outcomes than the control group, indicating preliminary evidence of effectiveness.