This pilot randomised controlled trial aims to assess the feasibility, acceptability, and preliminary efficacy of an intervention program promoting Mental Health Literacy. A 10-week group treatment, 90 minutes each session, for adults and older adults with Chronic Pain. Half of the participants will receive the intervention immediately (experimental group), while the other half will not receive it initially. Still, they will receive it after the main phase of the study is completed (control group in waiting list). The intervention focuses on increasing Mental Health Literacy and reducing maladaptive beliefs and behaviours associated with pain. It also explores mechanisms and moderators of change.

Chronic pain is a public health problem that negatively affects well-being and quality of life. In addition to its physiological aspect, pain is a subjective, complex and multidimensional experience. Depression, anxiety, and distress are among the most potent and robust predictors of the transition from acute to chronic pain. Furthermore, maladaptive psychological processes are risk factors for and/or worsening of chronicity and/or intensification of pain symptoms. Therefore, intervention in chronic pain should be a multimodal approach.

Although psychological interventions, particularly Cognitive Behavioral Therapy, are moderately effective in the treatment of pain, the psychoeducational component integrated into these programs has been limited to the biopsychosocial nature of chronic pain and the relationship between psychological distress and pain symptoms, neglecting the promotion of well-being and flourishing. In fact, chronic pain interventions have been almost exclusively limited to reducing symptoms of pain and mental illness, and less so to promoting well-being and overall mental health.

Mental health literacy interventions significantly influence help-seeking behaviours. These interventions, particularly in school settings, show promise in reducing stigma and improving knowledge and attitudes related to mental health. Their efficacy can vary, and there is a need for more tailored approaches to meet the specific needs of individual people. Although Mental Health Literacy is receiving increasing attention as an emerging area of study, it has been an unexplored area in the context of chronic pain. The current study aims to determine the feasibility and evaluate the "Learn to Act" programme -a group-based, mental health literacy intervention in people with chronic pain.

This pilot study seeks to address the following specific research questions: To what extent can the study effectively recruit participants who meet the inclusion criteria? How feasible are the data collection procedures and outcome measures for reaching the target population and evaluating the study objectives? Are the intervention and study procedures acceptable to participants and appropriate for the intended context? Does the research team possess the necessary resources and operational capacity to manage and deliver the intervention effectively? Finally, is the intervention preliminarily effective in increasing mental health literacy, positive affect, satisfaction with life, and quality of life related to spirituality, religiousness and personal beliefs, while reducing pain catastrophising, pain intensity, pain interference, and negative affect? General study design - Participants previously diagnosed with Chronic Pain by a physician will be assigned to two different groups: an experimental group that receives the intervention immediately, and a control group that does not receive the intervention initially but will receive it after the main phase of the study is completed. The feasibility and preliminary efficacy of the Mental Health Literacy Promotion Intervention Program will be assessed by comparing the groups.

Sample: The study will recruit adults and older adults with Chronic Pain. Patients will be provided a study description, a consent form and the research team contact for further clarifications.

The Mental Health Literacy Promotion Intervention Program has the following goals: (a) improve understanding of the pain-mental health connection, (b) reduce mental health stigma, (c) recognize symptoms of mental health challenges, and (d) encourage help-seeking behaviours.

Primary outcomes include changes in Mental Health Literacy and pain catastrophising. Secondary outcomes include quality of life, well-being, satisfaction with life, and pain interference/intensity. The study will assess feasibility through recruitment and retention rates, session attendance, and participant feedback. Mediators and moderators such as pain beliefs, religious coping, meaning in life, and demographic or clinical factors will also be explored to understand the process of change and differential responsiveness.

Inclusion Criteria:

• Adults (18 to 64 years old) and seniors (65 years old or older) residing in Portugal.
• Previous diagnosis of Chronic Pain carried out by a doctor.
• Availability to attend sessions.

Exclusion Criteria:

• Active neoplasia.
• Inability to give informed consent (e.g. due to dementia).
• Currently receiving psychological support regularly (sessions > once per semester).