Dyadic Psychological Stress Among Lung Cancer Patient-caregiver Dyads

The investigators measured dyadic depressive symptoms using the Patient Health Questionnaire-9 (PHQ-9), which is a 9-item questionnaire. Scores range from 0 to 27, with higher scores indicating more severe depression. According to Kroenke et al.'s scoring of the PHQ-9, a score of 0-4 indicates no depression, 5-9 indicates mild depression, 10-14 indicates moderate depression, 15-19 indicates moderate severe depression, and 20-27 indicates severe depression. The prevalence of depression is equal to the number of cases with a PHQ-9 score of 5 or greater divided by the total number of cases. Cronbach's alpha coefficients in this study were 0.85 and the KMO test value was 0.719, which showed good reliability and validity.

The investigators assessed anxious symptoms using the Generalized Anxiety Disorder-7 scale (GAD-7), which is a 7-item questionnaire. Scores range from 0 to 21, with higher scores indicating more severe anxiety. According to Spitzer et al's evaluation of GAD-7 scale, a score of 0-4 indicates no anxiety, 5-9 indicates mild anxiety, 10-14 indicates moderate anxiety, and 15-21 indicates severe anxiety. The prevalence of anxiety was defined as the number of cases with a GAD-7 score of 5 or greater divided by the total number of cases. Cronbach's alpha coefficients in this study were 0.93, respectively and KMO test value was 0.927, which showed good reliability and validity.

The investigators administered the Brief Illness Perception Questionnaire (BIPQ) to assess the dyads' cognitive and emotional reactions to illness. The scale has 9 items, with items 1-5 assessing cognition, items 6 and 8 assessing emotional status, item 7 assessing comprehension, and item 9 being an open-ended question about causality of the cause of the illness. Each item is scored on a scale of 0 to 10, and the total score ranges from 0 to 80, with higher scores indicating more negative perceptions of the illness. Cronbach's alpha coefficient in this study was 0.77.

The investigators used the Mindful Attention Awareness Scale (MAAS) to assess the dyads' mindfulness tendencies. The scale consists of 15 items and each item is assigned a score from 1 to 6, with the scale ranging from "almost always" to "almost never", with higher scores indicating higher levels of awareness and attention to the present moment. Cronbach's alpha coefficient in this study was 0.92.

The dyadic self-compassion was assessed using the Self-compassion Scale (SCS), which includes six dimensions of self-kindness, self-criticism, common humanity, loneliness, stillness, and over-indulgence, with a total of 26 items, has a high re-test reliability (r=0.93) and internal consistency reliability (α=0.92). Cronbach's α coefficient in this study was 0.88.

The Dyadic Coping Inventory (DCI)(32) was used to evaluate the coping ability of dyads. The Chinese version has a total of 37 items, including six dimensions: stress communication, support, negativity, empowerment coping, cooperation, and evaluation. A 5-point Likert scale was used, with higher scores indicating higher levels of positive dyadic coping, and the negative supportive coping items (items 7, 10, 11, 15, 22, 25, 26, 27) were reverse scored, with higher scores indicating higher levels of negative dyadic coping. A total score below 111 is considered low, a total score between 111 and 145 is considered moderate, and a total score above 145 is considered high. Cronbach's alpha coefficients in this study were 0.93.