Physiotherapy Intervention Program for Chronic Pain Associated With Depressive Disorder

Pain Catastrophizing Scale

This scale indicates the extent to which each of the 13 thoughts described is experienced. They are rated on a Likert scale ranging from 0 ('never') to 4 ('always'). The total score is calculated, with 52 being the maximum score. Low scores indicate low levels of catastrophising, whilst high scores indicate high levels of catastrophising.

Time frame: Baseline and Week 8

Chronic Pain Coping Questionnaire

The scale assesses the way in which patients cope with pain. It comprises six factors to be measured: religion, catharsis, distraction, mental self-control, self-affirmation and information-seeking. Within each factor there are between 5 and 6 items scored on a scale of 0 to 4, where 0 means 'strongly disagree' and 4 means 'strongly agree'. Greater use of active strategies such as distraction, self-affirmation or seeking information is associated with better emotional adjustment. Taken together, the score obtained provides an insight into how pain is coped with.

Time frame: Baseline and Week 8

Tampa Scale for Kinesiophobia (TSK-11)

11-item self-report questionnaire that assesses perceptions of frailty and the tendency to avoid movement for fear of injury or increased pain. Each item is scored on a 4-point scale (1: strongly disagree; 4: strongly agree). A high score on the TSK-11 indicates a greater fear of movement, a greater perception of physical frailty and a more pronounced tendency to avoid activities for fear of pain or injury. Conversely, low scores reflect lower kinesiophobia and a more confident attitude towards movement.

Time frame: Baseline and Week 8

Chronic Pain Self-Efficacy Questionnaire

This questionnaire consists of 19 items designed to assess the patient's confidence in their own ability to carry out various activities and manage the consequences of persistent pain. The scale is divided into three main domains or subscales: self-efficacy for pain control, for physical function and for symptom management. Each item is rated on a scale ranging from 0 ('completely unable') to 10 ('completely able'). A high score on this scale indicates a greater perceived ability to manage pain, maintain activity and manage symptoms, whilst low scores reflect lower confidence, greater dependence and poorer coping.

Time frame: Baseline and Week 8

Depression Anxiety Stress Scale (DASS-21)

The DASS-21 scale measures patients' emotional state and is used to assess three distinct areas: depression, anxiety and stress. This scale consists of 21 questions divided into three groups of seven items each. For each question, the patient must assign a score from 0 to 3, where 0 means that 'nothing has happened' and 3 means that 'it has happened a lot or most of the time'. Once completed, the points for each section (depression, anxiety and stress) are added together and the result is multiplied by 2 to obtain the final score for each category. Higher scores on each subscale indicate a greater presence of symptoms of depression, anxiety or stress, whilst lower scores reflect a better emotional state.

Time frame: Baseline and Week 8

Fear Avoidance Beliefs Questionnaire (FABQ)

This scale is based on patients' beliefs about how their pain affects their physical activity and work. This questionnaire consists of 16 items, of which 5 relate to beliefs regarding physical activity (FABQ-PA) - these are the items we will be assessing. Each item is rated on a Likert scale from 0 to 6, where 0 means 'strongly disagree' and 6 means 'strongly agree'. High scores indicate a high level of beliefs that lead to avoidance of activity.

Time frame: Baseline and Week 8

Clinical Global Impression Scale (CGI)

This scale assesses two aspects: the severity of the illness prior to treatment and the overall improvement following the intervention. It is a Likert-type scale ranging from 0 to 7. To assess the severity of the illness, 0 corresponds to 'not assessed' and 1 to 'normal, not ill', progressing up to 7, which represents 'among the most severely ill patients'. As regards overall improvement, 0 corresponds to 'not assessed', 1 to 'much better' and 7 to 'much worse'. It is a useful tool for assessing severity and response to treatment due to its practicality and clinical validity.

Time frame: Baseline and Week 8

Qualitative outcomes from focus groups

The focus-group sessions will be transcribed verbatim in full by a single researcher from the audio recordings. The transcripts will then be coded inductively and analysed independently by the research team. The analysis will begin at the most descriptive level, identifying units of meaning, which will be grouped into thematic codes-clusters of units of meaning referring to the same content, and progressively organised into categories, themes, and sub-themes until the main themes emerge. Beyond this descriptive coding, the analysis will move to an interpretive, inferential level, in which the team draws inferences about the meaning of the emerging themes rather than merely describing them. As this qualitative strand forms part of a mixed-methods design, these qualitative inferences will subsequently be integrated with the quantitative findings to generate meta-inferences, so that each strand informs and contextualises the other.

Time frame: Week 8