Thirty-nine individuals completed the intervention and quantitative assessment of the four indicators. They include 23 patients (70% females, mean age 65, 70% cancer diagnosis) and 16 carers (81% females, mean age 59, 50% spouse/partner), whose socio-demographic and/or medical data are shown in Tables 1 and 2 respectively. Twenty-nine people participated in semi-structured interviews (18 patients, 11 carers).
Intervention feasibility
As shown in Fig. 1, 340 patients were assessed for eligibility, 161 of whom were formally eligible (patients’ eligibility rate: 47%). We informed 138 patients, 38 of whom formally agreed to participate (patients’ participation rate: 28%). Eight patients were unable to start the study, and another seven dropped out during the study (patients’ attrition rate: 39%). Overall, 23 patients completed the study – 11 in phase 1, 12 in phase 2. One hundred patients refused to participate, mainly because they were not interested (49) or experienced health issues and fatigue (26). In turn, all the carers identified by patients were formally eligible (carers’ eligibility rate: 100%). We informed 24 carers about the study, 18 of whom were included (carers’ participation rate: 75%). Sixteen completed the study and two dropped out (carers’ attrition rate: 11%).
Twenty-three participants (17 patients, 6 carers) provided us with quantitative feasibility data on timeframe and transmission modalities. On average, participants took 1h10 to write their letters (min: 10mns, max: 4h30). All respondents found that the time allocated to the intervention (7 to 10 days) was sufficient. Transmission modality were heterogeneous: eight people exchanged their letters (by post or by hand), four read it aloud to the other, three read together silently, three were hesitant about sharing their letters, and one person wrote after the recipient (patient) had passed away. Data is missing for four participants. Overall, 15 patients and 15 carers completed the study as part of a dyad, and 8 patients completed it on their own, as did a carer, whose relative completed T0 only. Whilst the majority of participants (32/39; 82%) wrote their letter themselves, two were helped by their relative, three dictated their letter to a researcher or volunteers, and two audio-recorded their message with a researcher.
Thematic analysis of interview transcripts enabled us to identify three main intervention facilitators: (1) awareness of one’s own thoughts and feelings (“it seemed to me quite clear in fact, what I was grateful for”), which led some participant to experience letter-writing as self-evident (“the words were nearly ready to come out”); (2) ease with writing (“I write quite easily”); and (3) gratefulness in everyday life (“it’s an attitude that I cultivate”), which some participants experienced particularly strongly since the illness (“I’ve felt it [gratitude] more personally those past few years because of the illness”). Participants faced four main barriers: (1) written expression difficulties (the letter was “torn and torn again”); (2) physical difficulties (“I was very very tired”); (3) unprocessed memories (“there are things that I erased from my memories”); and (4) difficulties expressing or receiving gratitude (“I find it intimidating that someone can say “thanks” to me”).
Intervention effects
As shown in Table 3, we did not find any statistically significant change between T0 and T1 for patients. However, our quantitative results show a significant decrease in psychological distress for carers during the first phase of the study, in terms of depression (median = 3 at T0, 1.5 at T1, Z= -2.124, p = .034) and total score (median = 13 at T0, 7.5 at T1, Z=-2.045, p = .041), as shown in Table 4. We could not perform statistical analysis for carers in the second phase, as only 5 participated.
Table 3
Pre- and post-intervention quality of life, quality of relationship, psychological distress, and subjective burden for patients at phases 1 and 2
Patients
|
Median and interquartile range T0
|
Median and interquartile range T1
|
Statistical test - Z Wilcoxon
|
P-value
|
Phase 1 (n = 11)
|
|
|
|
|
Quality of life (MQOL-R)
|
|
|
|
|
Global (0–10)
|
7 (5–9)
|
7 (5–9)
|
− .427
|
.669
|
Physical (0–10)
|
5.7 (3.3–6.3)
|
5,7 (4–7)
|
-1.279
|
.201
|
Psychological (0–10)
|
6.5 (5.3–8.3)
|
5.3 (4.3–8.8)
|
− .714
|
.475
|
Existential (0–10)
|
7.5 (6.5–8.8)
|
7 (6.3–7.8)
|
− .666
|
.505
|
Relational (0–10)
|
9.7 (8.3–10)
|
8.7 (8.7–9.7)
|
-1.719
|
.086
|
Total score (0–10)
|
7.1 (6.2-8)
|
6.4 (5.8–7.2)
|
− .978
|
.328
|
Quality of relationship (PNRQ)
|
|
|
|
|
Positive scale (0–48)
|
43 (39–47)
|
42.8 (38–47)
|
− .634
|
.526
|
Negative scale (0–48)
|
0 (0–1)
|
0 (0–2)
|
− .447
|
.655
|
Quality of relationship (CSI-4; 0–21)
|
21 (18–21)
|
20 (18–21)
|
-1.414
|
.157
|
Psychological distress (HADS)
|
|
|
|
|
Depression (0–21)
|
7 (6–11)
|
6 (4–10)
|
− .655
|
.512
|
Anxiety (0–21)
|
6 (4–11)
|
7 (5–10)
|
− .104
|
.917
|
Total score (0–42)
|
14 (9–18)
|
15 (8–20)
|
− .535
|
.592
|
Subjective burden (SPBS; 0–50)
|
25 (21–32)
|
27 (24–32)
|
-1.179
|
.238
|
Phase 2 (n = 12)
|
|
|
|
|
Grateful relationship (0–5)
|
5 (5–5)
|
5 (5–5)
|
.000
|
1.000
|
Satisfactory relationship (0–5)
|
5 (5–5)
|
5 (5–5)
|
-1.000
|
.317
|
Quality of life (0–10)
|
7 (4.3–9.5)
|
6 (4–10)
|
− .171
|
.865
|
Grateful feeling (1–5)
|
5 (4–5)
|
5 (4–5)
|
− .378
|
.705
|
Depression (0–10)
|
.5 (0-4.8)
|
0 (0–5)
|
− .816
|
.414
|
Anxiety (0–10)
|
3.5 (0-5.75)
|
1 (0–6)
|
− .271
|
.786
|
Subjective burden (0–10)
|
6 (0–8)
|
3 (0–5)
|
− .775
|
.438
|
Table 4
Pre- and post-intervention quality of life, quality of relationship, psychological distress, and subjective burden for carers at phase 1
Carers (n = 11)
|
Median and interquartile range T0
|
Median and interquartile range T1
|
Statistical test - Z Wilcoxon
|
P-value
|
Quality of life (QOLLTI-F V2)
|
|
|
|
|
Global (0–10)
|
6 (3–8)
|
6.5 (4.75–8.25)
|
− .954
|
.340
|
Environment (0–10)
|
9.5 (8–10)
|
8.3 (7–10)
|
− .422
|
.673
|
Patient condition (0–10)
|
2 (1–6)
|
4 (1.8–5.8)
|
− .719
|
.472
|
Carer’s own state (0–10)
|
6.2 (4.8–7.4)
|
7 (5.3–8.5)
|
− .816
|
.415
|
Carer’s outlook (0–10)
|
7.3 (6–10)
|
7.5 (6.8–9.8)
|
− .341
|
.733
|
Quality of care (0–10)
|
9 (6.3–10)
|
8.3 (6.8–10)
|
− .170
|
.865
|
Relationships (0–10)
|
6.5 (4–8)
|
6.8 (5.5–9.3)
|
− .774
|
.439
|
Financial worries (0–10)
|
8 (2–10)
|
10 (1–10)
|
− .378
|
.705
|
Total score (0–10)
|
6.1 (5.9–7.2)
|
6.9 (6.1-8)
|
-1.172
|
.241
|
Quality of relationship (PNRQ)
|
|
|
|
|
Positive scale (0–48)
|
38 (32–45)
|
39 (33–43)
|
-1.246
|
.213
|
Negative scale (0–48)
|
2 (1–9)
|
1.5 ( (0-9.2)
|
− .677
|
.498
|
Quality of relationship (CSI-4, 0–21)
|
15 (14–19)
|
15 (13.8–18)
|
− .853
|
.394
|
Psychological distress
(BSI-18)
|
|
|
|
|
Depression (0–24)
|
3 (2–7)
|
1.5 (0-4.5)
|
-2.124
|
.034
|
Anxiety (0–24)
|
6 (2–8)
|
2 (1-4.5)
|
-1.527
|
.127
|
Somatisation (0–12)
|
1 (1–4)
|
0.5 (0-1.8)
|
-1.292
|
.196
|
Panic (0–12)
|
2 (1–4)
|
1 (0–2)
|
-1.611
|
.107
|
Total score (0–72)
|
13 (7–20)
|
7.5 (1.8–12.3)
|
-2.045
|
.041
|
Subjective burden (BSFC-s; 0–30)
|
14 (8–18)
|
14 (6.8–16.3)
|
-1.177
|
.239
|
Qualitative analysis indicates that overall, the intervention had: (1) multiple positive outcomes for 11 participants (5 patients, 6 carers), in the form of positive emotional and cognitive effects and, for five people, positive relational effects; (2) simple positive outcomes for 14 participants (9 patients, 5 carers), in the form of either emotional or cognitive effects; (3) no outcome for two patients; and (4) negative outcomes for two patients, in the form of negative emotional effects. We identified seven main effects of the gratitude intervention, which are depicted in Fig. 2 and described below. As a methodological side note, we decided to include data on prevalence (n) to our qualitative analysis in order to depict a precise picture of the intervention’s effects, provide rigorous information that could be relevant in terms of feasibility and acceptability of the intervention, and reinforce the mixed-methods character of our study.
Gladness. When narrating their experience of the intervention, 21 interviewees spoke of the gladness – understood as “a positive emotional response to circumstances” (40) – they felt when remembering past experiences, writing or sharing letters. Thirteen people mentioned feeling “good”, “happy”, “glad” or “pleased” (“it did me good to tell him again […] that I’m really grateful”, partner-patient; “it was like when we receive a gift, it was nice, it was sweet”, daughter-carer). A patient described a physiological response to memories of the life he shared with his wife, as “a sensation of wellbeing that went down there on the belly.” Eight participants further highlighted that they felt “moved” or “touched” by the intervention, and five noted that expressing their gratitude in a letter made them “feel light” or “was liberating”.
Anxiety, sadness. The intervention triggered negative emotions in five participants, who felt anxious about writing (“I was afraid of staying in front of a blank page”, sister-carer) or sharing the letter (“to read it in front of him I was maybe scared to have all of a sudden floods of tears”, wife-carer). For most, anxiety soon receded (“it worried me before and after I was very happy”, mother-patient). However, two participants experienced stronger anxiety and sadness during the intervention (“I was in mourning, I felt sorrow, even about gratitude, because everything I wrote, it was in the past”, partner-patient). We offered professional support to participants who experienced such effects.
Love and gratitude. Taking part in the intervention led three participants to feel strong emotions of love and gratitude. A daughter-carer said that remembering her childhood with her mother “gives love into the heart”, whilst a husband-patient related: “I even shed some tears whist writing this gratitude letter and telling myself “[…] What a marvellous wife I have!” […] I was in a very very strong, very positive emotion of absolute gratitude and love”.
Openness to emotions in everyday life. Four people were inspired by the intervention to express or practice gratitude more broadly (“to have written this letter makes me want to be more into gratitude, in a general way,” healthcare professional). Others opened up to their emotions more generally, as a sister-carer explained: “it enables me to allow myself my emotions.”
Personal strength. A fourth effect relates to a perceived increase in personal strength or worth, which was mentioned by six participants. Some people remarked that the intervention gave them the strength “to keep going forward” (partner-carer) or helped them be “more serene towards some reactions” (partner-carer). Others felt more worthy of gratitude (“if I feel low, blue, […] I can tell myself “ah yes, my wife also thanked me for something” husband-patient), or anticipated that the intervention might help them stay strong in the face of adversity (“by remembering the bond [with my mother], it can also help relationships afterwards, when everything goes wrong”, daughter-carer).
Heightened awareness. Eight participants mentioned gaining greater awareness of the other’s support (“those were moments I lived that are memorable, hard, painful for me and writing them, I realised [...] that I had a lot of help”, husband-patient), difficulties (“I thought about things I hadn’t thought of before […] in terms of what my husband is living through”, wife-carer), or gratitude (“since we did the letter, I realised that she was very grateful”, partner-relative). One patient further explained: “it made me understand a bit how I am on the inside […] in the illness and in pain,” which led him to “try to communicate differently when I feel I’m not well.”
Strengthened relationship. Five participants talked about the intervention as strengthening their relationship with their carer (“we were even better than before”, partner-carer; “We have this strength and we know it and we can lean on it and we know it’s shared”, husband-patient). For a carer, the intervention brought out a “much more altruistic, much stronger” dimension and “a truly strengthened bond” to his relationship with his partner.