Alexithymia in Family Caregivers of Advanced Cancer Patients Is Associated with High Personalized Pain Goal Scores: A Pilot Study

Abstract

Background:

Alexithymia, or difficulty identifying and describing emotions and sensations, contributes to an increased risk of chronic pain, and low help-seeking.

Objective:

To investigate whether family caregivers of advanced cancer patients visiting a palliative care department had alexithymia, and whether this was related to their pain intensity, personalized pain goals, and help-seeking for chronic musculoskeletal pain.

Design:

A single-center cross-sectional survey.

Measurements:

Pain intensity was evaluated using a numerical rating scale. Pain improvement was evaluated against personal goals. Alexithymia was assessed using the Toronto Alexithymia Scale-20 (TAS-20), and anxiety and depression using the Hospital Anxiety and Depression Scale.

Setting/Subjects:

Of 320 family caregivers visiting the palliative care department, 152 (47.5%) had chronic musculoskeletal pain; all 152 were included in the study.

Results:

Alexithymia was observed in 36.2% of participants. Participants with higher scores on the TAS-20 tended to have higher pain intensity scores and personal pain goal scores. TAS-20 score had the strongest correlation with personal pain goals, with a correlation coefficient of 0.555 (p < 0.001).

Conclusions:

Pain intensity in family caregivers with alexithymia tended to be high. These participants set higher personal pain goals (lower goals for symptom improvement) than those without alexithymia. We found no difference in personal pain goal response between family caregivers with and without alexithymia. When we examine pain in family members with alexithymia who are caring for cancer patients, we need to recognize that they may set higher personal pain goals and seek less help.

Background

The role of family members caring for cancer patients is demanding and may lead to increased morbidity and mortality.¹ Many of these caregivers have mental health problems, particularly depression and anxiety.^2,3 However, no previous studies have investigated physical pain in family members providing palliative care for cancer patients. One study on family members caring for cancer survivors found that 17.2% had chronic back pain (not including neck pain) two years after the initial cancer diagnosis.⁴ Advanced cancer patients tend to need intensive physical assistance, so carers may have chronic neck and back musculoskeletal pain from the physical strain of assisting with activities of daily living.⁵ Heart disease, arthritis, and chronic pain commonly cause disability.⁶ There is evidence that patient condition and caregiving duration are associated with depression.³

To the best of our knowledge, no previous studies have investigated whether and how family caregivers seek help for their own symptoms, such as chronic musculoskeletal pain. One study introduced mindfulness-based stress reduction to lung cancer patients and their family caregivers.⁷ This was effective for patients, but not for caregivers, probably because caregivers prioritized patients' well-being over their own. We hypothesized that family members caring for cancer patients might not seek help for chronic musculoskeletal pain for this reason. We therefore investigated pain intensity, pain improvement goals, and history of hospital treatment for chronic musculoskeletal pain among caregivers who visited the palliative care department with a family member with advanced cancer, rather than among family caregivers who visited hospitals about their own pain.

Alexithymia is a condition in which patients have difficulty identifying and describing sensations and emotions.⁸ One study of patients with chronic anxiety reported that alexithymia contributed to low help-seeking and hospital attendance.⁹ This may therefore be an additional reason why family caregivers may show low help-seeking behavior for their own symptoms. Alexithymia has been diagnosed in 8.9% to 27.6% of noncancer patients with chronic pain and in 50.5% of cancer patients with chronic pain.^10–12 However, the study with the lowest alexithymia rate (8.9%) had a very small sample of just 45.¹⁰

It has been suggested that alexithymia is associated with impaired interoception and that people with alexithymia tend to have poor awareness of their physical feelings.¹³ However, another study reported that pain intensity varies with the degree of alexithymia, and alexithymia is related to chronic pain in the general population.¹⁴ Alexithymia intensifies physical symptoms such as pain in cancer patients.^15,16 We hypothesized that family caregivers with alexithymia may not adequately recognize either their pain intensity or their pain improvement goals, because they have poor awareness of how they feel. Alexithymia may make people less likely to seek help for pain, so it is clinically important to investigate the relationship between alexithymia and pain improvement goals in family caregivers in a palliative care setting.

Personalized pain goals (PPGs), which are patient-reported outcomes in pain management, are important in palliative medicine. They are the treatment goals of pain management, and patients indicate them with a subjective numerical rating scale.¹⁷ Their use has improved quality of care and contributed to the medical economy.¹⁸ A positive PPG response is defined as a decrease in pain intensity to the level of the goal or lower. In studies of cancer patients, 35% to 45% achieved their PPG and 80% did not need further analgesic treatment.^19,20 In cancer patients, achieving the PPG is associated with lower pain intensity, lower opioid dose, less adjuvant analgesic administration, and less depression.²⁰

However, there may be cases with both higher pain intensity and high PPGs, which may make PPGs less likely to be achieved, for example, if people set their PPG high by repressing their pain and emotional distress. This may be the case in family caregivers, and awareness of this is important for clinical work. The factors that influence individual PPGs are unclear.

The main objective of this study was to describe any association between degrees of alexithymia and PPG scores among family caregivers of cancer patients receiving palliative care.

Methods

Objective

We aimed to investigate whether family caregivers of advanced cancer patients visiting a palliative care department had alexithymia, and whether this was related to their pain intensity, PPGs, and help-seeking for chronic musculoskeletal pain.

Study design

This study was a cross-sectional survey of family caregivers with chronic musculoskeletal pain in Osaka, a city in western Japan. We collected demographic information, including age, sex, relationship with the cancer patient, site of chronic pain, and current medical treatment for pain, measures of pain intensity, goals for pain improvement (PPG), and self-reported questionnaires about alexithymia, anxiety, depression, and caregiver burden. We also collected demographic information about the family member with cancer, including age, sex, outpatient status, primary cancer site, and performance status. Prognostic information about the patients was assessed six months after the survey by review of medical records and inquiries to the hospice institution. The study received approval from the Medical Ethics Committee of the Kansai Medical University (reference number: 2015660).

Study participants

This study was conducted from 2016 to 2018 at the Kansai Medical University Hospital. During this period, 823 family caregivers of advanced cancer patients visited the palliative care department, of whom 503 were excluded because they (1) were younger than 20 years (n = 9), (2) had cognitive impairments that made communication difficult (n = 69), and (3) did not want to participate (n = 425). A total of 320 family caregivers were enrolled in the study, of whom 152 (47.5%) had chronic musculoskeletal pain and were included in the study. None dropped out after enrollment.

Family caregivers were defined as family members directly providing care for a relative with cancer, including spouses. Chronic musculoskeletal pain followed the definition and classification of the International Association for the Study of Pain.²¹ The definition of “chronic” has not been clearly established, but duration of at least three to six months is generally used.²² We defined chronic pain in this study as any subjective pain present for more than six months.

Instruments

Pain intensity

Participants evaluated their average pain intensity in the previous 24 hours using an 11-point numerical rating scale, ranging from 0 (no pain) to 10 (worst possible pain).²³ The reliability and validity of this scale have been established.²⁴

Pain improvement goal

PPGs were assessed by asking participants, “What is the maximum level of pain that you would feel comfortable with?” Participants indicated their responses using the 11-point scale. The PPG is considered to be fixed.^17,20 PPGs were considered achieved if participants' average pain intensity in the previous 24 hours was lower than or equal to the PPG.^19,20

Hospital consultation history for chronic musculoskeletal pain

We asked whether family caregivers had attended any hospital consultations to diagnose and treat their chronic musculoskeletal pain since its onset.

Toronto Alexithymia Scale-20

Participants completed the Japanese version of the Toronto Alexithymia Scale-20 (TAS-20) to evaluate alexithymia symptoms. The TAS-20 is a self-reported questionnaire containing 20 items using a rating scale from 1 to 5, producing a total score from 20 to 100. It has three subcategories: difficulty identifying feelings (seven items), difficulty describing feelings (five items), and externally oriented thinking (eight items). Adequate validity and reliability of the TAS-20 have been reported in previous studies,^25,26 with high construct validity and reliability established for the Japanese version.²⁷ Participants were classified into three groups by total TAS-20 score: nonalexithymic (≤51), borderline (52–60), or alexithymic (≥61).²⁸

Hospital Anxiety and Depression Scale

Each participant completed the Hospital Anxiety and Depression Scale (HADS) to evaluate levels of anxiety and depression.^29,30 This scale includes 14 items (the score for each ranges from 0 to 3), 7 for the anxiety subscale (HADS-A, 0–21) and 7 for the depression subscale (HADS-D, 0–21). Higher scores indicate more severe emotional distress. In this study, an HADS-A/HADS-D score of 8 or more was considered indicative of anxiety or depression. These cutoff points provide the optimal balance between sensitivity and specificity.²⁹

Japanese version of Zarit Caregiver Burden Interview

The level of nursing care burden felt by the caregiver was evaluated using the Japanese version of Zarit Caregiver Burden Interview (J-ZBI). A J-ZBI score of 24 or higher, the cutoff value for depression risk, was considered indicative of high caregiver burden.³¹

Sample size calculation

The estimated number of patients required to detect a minimum PPG difference of 1.0 (standard deviation, 2.0) between the three groups was 150 (n = 50 in each group), estimated from published data (there are no PPG data for family caregivers, so data for cancer patients were used). The significance was set at 0.05 and power at 80%.^17,19

Statistical analyses

Data are reported as mean with standard deviation, ranges, or frequencies (%), as appropriate. We analyzed associations between demographics; rating scale score; PPG score; PPG achievement; treatment for chronic musculoskeletal pain; and TAS-20, HADS, and J-ZBI scores using the Kruskal–Wallis test, Wilcoxon rank-sum test, and chi-square test. For items where the Kruskal–Wallis test indicated significant differences, the Bonferroni method was used for a multiple comparison. Spearman's rank correlation coefficients were calculated to assess associations between PPG and rating scale score, age, total and subscale TAS-20 scores, HADS-A and HADS-D scores, and J-ZBI score.

A p-value less than 0.05 was considered statistically significant. Statistical analyses used SPSS version 25.0J for Macintosh (SPSS, Inc., IBM, Chicago, IL).

Results

The demographic and clinical characteristics of study participants and care recipients are shown in Table 1.

Table 1.

Demographic and Clinical Characteristics of the Study Participants and the Patients

Study participants (family caregiver)		Patients (family members with advanced cancer)
Age (years), mean (SD)	61.8 (14)	Age (years), mean (SD)	68.3 (11.9)
Sex, n (%)		Sex, n (%)
Male	30 (19.7)	Male	88 (57.9)
Female	122 (80.3)	Female	64 (42.1)
Relationship with the patients, n (%)		Outpatients, n (%)	74 (48.7)
Wife	81 (53.3)	Primary cancer site, n (%)
Husband	26 (17.1)	Lung	21 (13.8)
Daughter	26 (17.1)	Gastrointestinal	58 (38.2)
Son	4 (2.6)	Liver, pancreas, biliary system	22 (14.5)
Mother	8 (5.3)	Breast	20 (13.2)
Sibling	7 (4.6)	Gynecological	8 (5.3)
NRS score, median (IQR)	3 (2–5)	Urological	10 (6.6)
Site of the chronic pain, n (%)		Head and neck	11 (7.2)
Neck	84 (55.3)	Others	2 (1.2)
Back	72 (47.4)	ECOG PS, n (%)
Extremities	24 (15.8)	0	0 (0)
PPG score, median (IQR)	3 (2–5)	1	26 (17.1)
PPG achievement, n (%)	102 (67.1)	2	34 (22.3)
Hospital consultation history for pain, n (%)	10 (6.6)	3	47 (30.9)
TAS-20 total score, mean (SD)	55.4 (16.7)	4	36 (23.7)
TAS-20 DIF	16.4 (7.4)	Duration from survey until death, days, n (%)
TAS-20 DDF	16.6 (7.5)	≥90	66 (43.4)
TAS-20 EOT	22.4 (5.9)	91–180	35 (23)
HADS-A, mean (SD)	7.1 (4.5)	181≥	39 (25.7)
HADS-D, mean (SD)	7.3 (4.9)	Unknown	12 (7.9)
J-ZBI, mean (SD)	30.5 (18.2)		12 (7.9)

DDF, difficulty describing feelings; DIF, difficulty identifying feelings; EOT, externally oriented thinking; HADS-A, Hospital Anxiety and Depression Scale-Anxiety; HADS-D, Hospital Anxiety and Depression Scale-Depression; IQR, interquartile range; J-ZBI, Japanese version of Zarit Caregiver Burden Interview; NRS, numerical rating scale; PPG, personalized pain goal; PS, performance status; SD, standard deviation; TAS, Toronto Alexithymia Scale.

Table 2 shows demographics, numerical rating scale scores, PPG scores, PPG achievement, and current treatment for chronic musculoskeletal pain by TAS-20, HADS, and J-ZBI scores. Alexithymia was observed in 55 participants (36.2%), anxiety in 68 (44.7%), and depression in 71 (46.7%). Participants with high TAS-20 scores tended to have higher pain ratings and PPG scores than other participants. Multiple comparisons showed a significant difference in the rating score between the nonalexithymia and alexithymia groups (p = 0.001). The numerical score was also higher in the borderline group than in the nonalexithymia group, but the difference was not significant (p = 0.199). There were significant differences in PPG score between the nonalexithymia group and both the borderline and alexithymia groups (p = 0.016 and p < 0.001) and between the borderline and alexithymia groups (p = 0.001).

Table 2.

Numerical Rating Scale and Personalized Pain Goal Score According to the Score Level of the Toronto Alexithymia Scale-20, the Hospital Anxiety and Depression Scale, and the Zarit Caregiver Burden Interview

	TAS-20 score			p-Value	HADS-A		p-Value	HADS-D		p-Value	J-ZBI		p-Value
	Nonalexithymia	Borderline alexithymia	Alexithymia	p-Value	Nonanxiety	Anxiety	p-Value	Nondepression	Depression	p-Value	Low caregiver burden	High caregiver burden	p-Value
	≦51	52–60	≥61		<8	≥8		<8	≥8		<24	≥24
No. of subjects	65	32	55		84	68		81	71		61	91
Age (years), mean (SD)	64.0 (11.6)	60.7 (15.2)	57.5 (15.1)	0.674	59.3 (15.0)	61.9 (12.5)	0.486	59.5 (15.0)	62.0 (12.5)	0.596	59.2 (13.8)	61.6 (14.0)	0.254
Sex, female, (%)	81.5	84.4	78.2	0.767	83.3	76.5	0.197	86.4	72.9	0.017	77.0	82.4	0.270
NRS score, median (IQR)	2 (1–3)	3 (2–5.5)	3 (3–5)	0.002	3 (1–5)	3 (2–6)	0.188	3 (1–5)	3 (2–6)	0.329	3 (1–5)	3 (2–6)	0.376
PPG score, median (IQR)	2 (1–3)	3 (2–3.5)	5 (3–6)	<0.001	3 (2–5)	3(2–3.5)	0.321	3 (2–5)	3 (2–3)	0.179	3 (2–4)	3 (2–5)	0.176
PPG achievement (%)	66.2	71.9	65.5	0.809	73.8	58.8	0.038	71.6	60.6	0.124	68.9	65.9	0.423
Hospital consultation history for pain (%)	6.2	9.4	5.5	0.769	2.4	11.8	0.023	2.5	11.3	0.021	4.9	7.7	0.374

The PPG score was correlated with pain score (p < 0.001), TAS-20 score (p < 0.001), and J-ZBI score (p = 0.029) (Table 3). The largest correlation coefficient was with TAS-20 score (0.555).

Table 3.

Correlation Coefficient between Personalized Pain Goal Score and Numerical Rating Scale Score, the Toronto Alexithymia Scale-20, the Hospital Anxiety and Depression Scale, and the Zarit Caregiver Burden Interview

	PPG	NRS	Age	TAS-20 total	DIF	DDF	EOT	HADS-A	HADS-D
PPG
NRS	0.402^***
Age	0.066	0.121
TAS-20 total	0.555^***	0.208^*	0.041
DIF	0.653^***	0.257^**	0.056	0.865^***
DDF	0.393^***	0.262^**	0.012	0.865^***	0.655^***
EOT	0.221^**	−0.120	0.014	0.636^***	0.355^***	0.399^***
HADS-A	−0.108	0.084	0.072	−0.128	−0.104	−0.131	−0.027
HADS-D	−0.089	0.052	0.040	−0.122	−0.070	−0.107	−0.058	0.774^***
J-ZBI	0.177^*	0.154	0.252^**	0.222^**	0.200^*	0.176^*	0.145	0.186^*	0.194^*

p < 0.05.

p < 0.01.

***

p < 0.001.

Discussion

As far as we know, this is the first study among family caregivers of advanced cancer patients to report that those with alexithymia set higher PPGs than those without. The reported median PPG of cancer patients is 2–6,^17,19,20 similar to the median PPG of 3 in our study cohort. However, the median PPG among participants with alexithymia was 5, which is rather higher. Two-thirds of the family caregivers had J-ZBI ≥ 24, suggesting that they felt the burden of caring for patients in the palliative care stage. However, they were very unlikely to have sought help for their pain: just 6.6% were receiving current treatment.

The most important finding of this study was that participants with alexithymia had a relatively high rate of PPG achievement (65.5%) and that there was no difference in PPG response rate between those with and without alexithymia. The reported PPG response rate among cancer patients with chronic pain is 30% to 45%.^17,20 The pain scores of caregivers with alexithymia in this study was high, which is similar to previous findings.^14–16 Our results suggest that the degree of alexithymia positively correlates with the PPG. We found correlations between PPGs and the three alexithymia subscales. The subscale with the strongest correlation was difficulty identifying feelings, and then, difficulty describing feelings. These findings suggest that caregivers with alexithymia probably set higher PPGs because they unconsciously have difficulty identifying and describing pain.

There was no significant difference in PPG response between participants with and without alexithymia. This suggests that individuals with alexithymia tended to ask for help when their symptoms became severe. Pain intensity in participants with alexithymia was likely to be high, but they set higher PPGs than those without alexithymia. The percentage of participants with alexithymia who were currently receiving treatment for pain was 5.5%, which was low, but similar to the percentage without alexithymia. A study of patients with chronic anxiety reported that alexithymia contributed to low help-seeking and hospital attendance rates.⁸ Family members caring for cancer patients may feel guilty about prioritizing their own well-being over that of the patient.⁷ Taken together, these findings suggest that family caregivers with alexithymia rarely seek help.

We suggest that this is because alexithymia makes it difficult for people to deal with their pain, because it prevents recognition of hypertension in the muscle fascia as a warning signal. Alexithymia is associated with latent trigger points in the muscle fascia of healthy individuals without chronic pain.³²

We suggest that people with alexithymia may set a higher PPG than others because they are unable to recognize the pain of an active trigger point as a danger signal. Alexithymia therefore results in decreased help-seeking, which causes increased pain intensity and worsening symptoms. One study found that the degree of alexithymia was positively correlated with pain intensity in individuals with chronic musculoskeletal pain.⁹ In our study, a relatively high percentage of family members caring for cancer patients (36.2%) had alexithymia. We need to recognize that we have many chances to engage with these caregivers, that they may set higher PPGs for pain management (lower goals for symptom improvement), and that they are less likely to seek help.

This study had the following limitations. First, many eligible family caregivers refused to participate. This may be because we recruited family caregivers who accompanied patients to a hospital visit, and they prioritized the patient's well-being over their own.

Second, caregivers with musculoskeletal pain who had not visited a hospital were diagnosed based only on a medical interview. Additional assessment was not possible, because the caregivers were accompanying family members to the palliative care department, not attending a consultation for their pain. Future studies on family caregiver experience should incorporate a more in-depth diagnosis of pain. In this study, a very high percentage of family caregivers (47.5%) had chronic musculoskeletal pain. A previous study found a much lower proportion (17.2%) but targeted cancer survivors, and was limited to the lower back.⁴ Advanced cancer patients tend to need intensive physical assistance, so family caregivers may develop chronic musculoskeletal pain from physical strain.⁵ Two-thirds of patients were in the palliative care stage, with death occurring within 180 days of the survey.

Third, the PPG is a pain improvement goal developed for pain management of cancer patients and no previous studies have investigated PPGs in family caregivers. However, there is no valid measure of pain improvement goals in this group, so PPGs were considered the best option. The median PPG score for study participants was 3, the same as in previous studies of cancer patients.^17,20

Fourth, some studies have reported that alexithymia is associated with anxiety and depression in patients with chronic pain, but we found no correlation between alexithymia and anxiety or depression.^33,34 Only 6.6% of family caregivers with pain were receiving hospital treatment. Previous studies, however, included only patients with chronic pain who had visited a hospital.^33,34 It may therefore be difficult to compare our results with those of previous studies. It is also possible that people with different alexithymia subtypes may have different relationships between these measures. For example, type B alexithymia is associated with greater difficulties in identifying feelings and a higher prevalence of self-reported major depressive disorder than type A.³⁵ However, we could not identify the prevalence of different types of alexithymia in study participants because all three subcategory scores were high.³⁶

Finally, the study was carried out at a single site, so the findings may not be generalizable to other settings. Larger, multisite studies are needed in the future. This may therefore be considered a pilot study.

Conclusions

Family caregivers with alexithymia tended to have high pain intensity, but set higher PPGs than those without alexithymia. We found no difference in PPG response between caregivers with and without alexithymia. Higher PPGs were associated with difficulty identifying and describing feelings. We therefore need to recognize that family caregivers with alexithymia may set high PPGs for pain management (low goals for symptom improvement) and are unlikely to seek help. We should therefore be careful in working with these caregivers to ensure that their needs are met.

Footnotes

Acknowledgments

The authors thank the palliative care team members of the Kansai Medical University Hospital. They thank Susan Furness, PhD, and Melissa Leffler, MBA, from the Edanz Group () for editing a draft of this article.

Funding Information

This work was supported by an Imai Kimi Memorial Stress-Related Disease Research Grant Fund.

Author Disclosure Statement

No competing financial interests exist.

References

Williams

: Family caregivers to adults with cancer: The consequences of caring. Recent Results Cancer Res, 2018; 210:87–103.

Oechsle

, Goerth

, Bokemeyer

, et al.: Anxiety and depression in caregivers of terminally ill cancer patients: Impact on their perspective of the patients' symptom burden. J Palliat Med, 2013; 16:1095–1101.

Geng

, Chuang

, Yang

, et al.: Prevalence and determinants of depression in caregivers of cancer patients: A systematic review and meta-analysis. Medicine (Baltimore), 2018; 97:e11863.

Kim

, Carver

, Shaffer

, et al.: Cancer caregiving predicts physical impairments: Roles of earlier caregiving stress and being a spousal caregiver. Cancer, 2015; 121:302–310.

Kim

, Schulz

: Family caregivers' strains: Comparative analysis of cancer caregiving with dementia, diabetes, and frail elderly caregiving. J Aging Health, 2008; 20:483–503.

Center for Disease Control and Prevention (CDC): Disability and Health, 2011. Atlanta, GA: CDC, 2011. http://www.cdc.gov/ncbddd/disabilityandhealth/data.html. (Last accessed July 1, 2016).

Schellekens

MPJ

, van den Hurk

DGM

, Prins

, et al.: Mindfulness-based stress reduction added to care as usual for lung cancer patients and/or their partners: A multicentre randomized controlled trial. Psychooncology, 2017; 26:2118–2126.

Sifneos

: The prevalence of ‘alexithymic’ characteristics in psychosomatic patients. Psychother Psychosom, 1973; 22:255–262.

Rufer

, Moergeli

, Moritz

, et al.: Alexithymia and non-treatment: An Internet based study of 312 people with chronic anxiety. Compr Psychiatry, 2014; 55:179–187.

10.

Castelli

, De Santis

, De Giorgi

, et al.: Alexithymia, anger and psychological distress in patients with myofascial pain: A case-control study. Front Psychol, 2013; 4:490.

11.

Okanli

, Karabulutlu

, Asi

Karakaş

. S, et al.: Alexithymia and perception of illness in patients with cancer. Eur J Cancer Care, 2018; 27:e12839.

12.

Di Tella

, Castelli

: Alexithymia in chronic pain disorders. Curr Rheumatol Rep, 2016; 18:41.

13.

Ikemi

, Ikemi

: An oriental point of view in psychosomatic medicine. Psychother Psychosom, 1986; 45:118–126.

14.

Shibata

, Ninomiya

, Jensen

, et al.: Alexithymia is associated with greater risk of chronic pain and negative affect and with lower life satisfaction in a general population: The Hisayama Study. PLoS One, 2014; 9:e90984.

15.

Grassi

, Caruso

, Nanni

: Somatization and somatic symptom presentation in cancer: A neglected area. Int Rev Psychiatry, 2013; 25:41–51.

16.

Tulipani

, Morelli

, Spedicato

, et al.: Alexithymia and cancer pain: The effect of psychological intervention. Psychother Psychosom, 2010; 79:156–163.

17.

Dalal

, Hui

, Nguyen

, et al. Achievement of personalized pain goal in cancer patients referred to a Supportive Care Clinic at a comprehensive cancer center. Cancer, 2012; 118:3869–3877.

18.

Zylla

, Larson

, Chuy

, et al.: Establishmentofpersonalizedpaingoalsinoncologypatientstoimprovecareanddecreasecosts. J Oncol Pract, 2017; 13:266–272.

19.

Watanabe

, Miura

, Okizaki

, et al.: Comparison of indicators for achievement of pain control with a personalized pain goal in a comprehensive cancer center. J Pain Symptom Manage, 2018; 55:1159–1164.

20.

Arthur

, Tanco

, Park

, et al.: Personalized pain goal as an outcome measure in routine cancer pain assessment. J Pain Symptom Manage, 2018; 56:80–87.

21.

Treede

, Rief

, Barke

, et al.: A classification of chronic pain for ICD-11. Pain, 2015; 156:1003–1007.

22.

Dworkin

, Turk

, Peirce-Sandner

, et al.: Research design considerations for confirmatory chronic pain clinical trials: IMMPACT recommendations. Pain, 2010; 149:177–193.

23.

Caraceni

, Cherny

, Fainsinger

, et al.: Pain measurement tools and methods in clinical research in palliative care: Recommendations of an Expert Working Group of the European Association of Palliative Care. J Pain Symptom Manage, 2002; 23:239–255.

24.

Hawker

, Mian

, Kendzerska

, et al.: Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP). Arthritis Care Res (Hoboken), 2011; 63 Suppl 11:S240–S252.

25.

Bagby

, Parker

, Taylor

: The twenty-item Toronto Alexithymia Scale—I. Item selection and cross-validation of the factor structure. J Psychosom Res, 1994; 38:23–32.

26.

Bagby

, Taylor

, Parker

: The Twenty-item Toronto Alexithymia Scale—II. Convergent, discriminant, and concurrent validity. J Psychosom Res, 1994; 38:33–40.

27.

Moriguchi

, Maeda

, Igarashi

, et al.: Age and gender effect on alexithymia in large, Japanese community and clinical samples: A cross-validation study of the Toronto Alexithymia Scale (TAS-20). Biopsychosoc Med, 2007; 1:7.

28.

Taylor

, Bagby

, Parker

: Disorder of Affect Regulation: Alexithymia in Medical and Psychiatric Illness. Cambridge, United Kingdom: Cambridge University Press, 1997.

29.

Bjelland

, Dahl

, Haug

, et al.: The validity of the Hospital Anxiety and Depression Scale. An updated literature review. J Psychosom Res, 2002; 52:69–77.

30.

Matsudaira

, Igarashi

, Kikuchi

, et al.: Factor structure of the Hospital Anxiety and Depression Scale in Japanese psychiatric outpatient and student populations. Health Qual Life Outcomes, 2009; 7:42.

31.

Schreiner

, Morimoto

, Arai

, et al.: Assessing family caregiver's mental health using a statistically derived cut-off score for the Zarit Burden Interview. Aging Ment Health, 2006; 10:107–111.

32.

Hasuo

, Kanbara

, Abe

, et al.: Relationship between alexithymia and latent trigger point points in the upper trapezius. Bio Psychosocial Med, 2017; 11:31.

33.

Zeng

, Sun

, Yang

, et al.: Life events, anxiety, social support, personality, and alexithymia in female patients with chronic pain: A path analysis. Asia Pac Psychiatry, 2016; 8:44–50.

34.

Saariaho

, Saariaho

, Mattila

, et al.: Alexithymia and depression in a chronic pain patient sample. Gen Hosp Psychiatry, 2013; 35:239–245.

35.

Kajanoja

, Scheinin

, Karlsson

, et al.: Illuminating the clinical significance of alexithymia subtypes: A cluster analysis of alexithymic traits and psychiatric symptoms. J Psychosom Res, 2017; 97:111–117.

36.

Ueno

, Maeda

, Komaki

: Different subgroups of high-scorers on the TAS-20 based on the big five personality traits. Pers Individ Dif, 2014; 68:71–76.