Preliminary findings from a previous study conducted by the investigators suggest that a task-shared approach with modified mindfulness-based cognitive therapy (MBCT) supported by social workers is beneficial in managing depressive symptoms and improving mindful non-reactivity among older adults. However, the possibility for social workers to lead a mindfulness-based intervention (MBI) independently to improve its scalability and service accessibility remains unclear. The project aims to:

1. Evaluate the effectiveness of social worker-led MBI in improving depression in older adults with mild to moderate depressive symptoms as compared to care as usual;
2. Examine the effectiveness of incorporating peer supporters in social worker-led MBI compared to those without peer supporters;
3. To identify potential mechanisms of change in MBI for depressive symptoms.

Mindfulness-based cognitive therapy (MBCT) is a promising approach to managing a series of health and psychological conditions among older adults. To increase its acceptability, feasibility, and scalability, MBCT has been adapted and delivered in a variety of formats. Apart from delivering the intervention in person by a certified mindfulness teacher, MBCT has been adapted to be self-taught, delivered online, or partially led by social workers.

In a previous study conducted by the investigators, it was found that a task-shared approach with modified MBCT supported by social workers is effective in producing change in older adults' mental health and mindfulness. However, whether social workers are competent to lead a mindfulness-based intervention (MBI) informed by MBCT on their own and produce effective changes in outcome measures pertaining to mental health remains unclear.

Furthermore, the effects of incorporating peer supporters into mental health interventions are unclear. The uses and implementation of peer support across mental health contexts vary greatly and the effects are mixed. In a pilot study on men with advanced prostate cancer, it has been suggested that the presence of peer support in modified mindfulness-based cognitive therapy group intervention may reinforce intervention effects. Furthermore, in an online intervention for older adults with elevated depressive symptoms, peer support has been found to improve engagement and adherence to the intervention. However, in a systematic review and meta-analysis, it has been found that while incorporating one-to-one peer support in mental health services has a modest positive impact on self-reported psychosocial outcomes such as self-rated recovery and empowerment, there is no evidence for improvement in clinical outcomes.

With the growing older people population and a need for greater social welfare capacity to promote older adults' well-being, the current study aims to examine the effectiveness of social worker-led MBI informed by MBCT in improving depression in older adults with mild to moderate depressive symptoms. In addition, the effectiveness of incorporating peer supporters into the intervention will be examined.

Inclusion Criteria:

• 60 years or older
• have depressive symptoms of mild level or above, as indicated by scoring 5-14 on PHQ-9
• can give informed consent to participate

Exclusion Criteria:

• known history of autism, intellectual disability, schizophrenia-spectrum disorder, bipolar disorder, Parkinson's disease, or dementia
• current abuse of drugs or alcohol
• difficulty in communication
• imminent suicidal risk
• timing or training is unsuitable for the participant