Ruriko Kidachi, RN, PhD, Department of Development and Aging, Division of Health Sciences, Graduate School of Health Sciences, Hirosaki University, 66-1 Hon-cho, Hirosaki-shi, Aomori-ken 036–8564, Japan. Email: email@example.com
Abstract The aim of this study was to obtain information that would enable caregivers to provide the necessary psychological care for hemodialysis patients. A total of 608 hemodialysis patients completed the questionnaire of the Neuroticism, Extroversion, Openness–Five Factor Inventory and were subsequently classified by personality types using cluster analysis. In comparison to the norms for the general Japanese adult population, the four-dimensional average of extroversion, openness, agreeableness, and conscientiousness among hemodialysis patients was significantly lower (P < 0.001), especially for openness. The openness score correlated with each of the following: age (P < 0.001), employment (P < 0.01), and diabetes (P < 0.001). Four personality types were defined based on these dimensions. High scores for agreeableness, extroversion and conscientiousness characterized the agreeable type (22.6%). The patients in this type will likely accept their own experiences in a positive manner. Submissive types (22.0%) received the lowest scores for conscientiousness, though extroversion, openness, and agreeableness were also low. It is necessary to enhance a sense of independence and responsibility in patients with submissive type personalities. Sensitive types (21.5%) were characterized by the highest neuroticism scores and low scores for the other four dimensions. The patients in this type were likely to be persistent with changes in conditions. The last type was the balanced type (33.9%), which was defined by scores within mean range. In clinical practice, it is particularly important that the submissive and sensitive types should receive appropriate mental health care.
The number of patients receiving hemodialysis is increasing annually in Japan, with the number of patients receiving treatment reaching 257 765 in 2005 (according to the Japan Association of Kidney Disease Patients, 2006). Dialysis patients are constantly aware of their physical deficiency, yet they also face serious life-threatening complications caused by hemodialysis, such as disequilibrium syndrome. In addition to these factors, restrictions of diet and fluids, as well as limited occupational and social activities, are reported to cause stress in dialysis patients.1,2 Recently, the age of long-term dialysis patients and the mean age at dialysis initiation have increased. For elderly dialysis patients, the physical inconvenience associated with aging, as well as social and economic difficulties, also contribute to stress. Consequently, it is necessary for caregivers and health-care professionals to understand the psychological status of hemodialysis patients.
The mental health care of hemodialysis patients requires collaborative treatments in which people with a variety of backgrounds are involved, with psycho-nephrology (counseling and drug administration) by psychiatrists being primary. However, providing care according to the patient's mental condition at a given time, as well as taking into account an individual's background, the course of the illness, and his/her mental status are difficult and often left to the individual's discretion.
Many of the previously reported studies on the mental health aspects of hemodialysis have used various scales to quantitatively examine the relationship between outcomes such as quality of life, self-management or adherence, and the patient's background.3 For instance, there are some studies to clarify stress-coping mechanisms,4–7 the relationship between self-management behaviors, and self-efficacy of dialysis patients.8–11 Despite the fact that patient outcomes seem to vary according to mental status, only few investigations on the relationship between behavior and personality have been conducted.12–15 The authors assumed that if personality types could be identified, appropriate caregiving methods could be devised based on these types. Therefore, this study aimed to classify personality types of hemodialysis patients.
In 2002, a cross-sectional study using random sampling was conducted by mailed questionnaires. The authors explained the purpose of the study to a responsible person at a self-help association for hemodialysis patients located in Aomori prefecture, Japan, and obtained permission to question its members. Disclosure and informed consent forms were enclosed in envelopes with questionnaires based on the Neuroticism, Extroversion, Openness–Five Factor Inventory (NEO-FFI).
The NEO-FFI consists of a total of 60 items, with 12 items for each of the five main personality dimensions from the 240 items of the Revised NEO Personality Inventory (NEO-PI-R). It is a self-report study, rated on a 5-point Likert-type scale. The Japanese versions of the NEO-PI-R and the NEO-FFI have been translated and standardized, and reliability has also been obtained.16
The neuroticism dimension includes facets such as anxiety, angry-hostility, depression, self-consciousness, and vulnerability. The extroversion dimension includes facets such as warmth, gregariousness, assertiveness, activity, excitement, and other positive emotions. The openness dimension includes facets such as fantasy, aesthetics, feelings, actions, ideas, and values. The agreeableness dimension includes facets such as trust, straightforwardness, altruism, and compliance. Finally, the conscientiousness dimension includes facets such as order, dutifulness, achievement striving, determination, and self-discipline.
The envelopes were distributed to 1700 members of the self-help association via contact persons of the branch association and collected after 20 days. The location from which patients replied was not recorded, but many respondents filled out the questionnaires on dialysis beds.
Patients were deemed to have given their consent for the study when their replies were received. The response rate was 44.1% and the number of valid responses was 608. The authors believe that the response rate was low because it was not possible to obtain responses from patients who had difficulty completing the questionnaires without help.
Several statistical tests were conducted to analyze the data. The Pearson's rank correlation analysis was performed to examine the relationship among the five dimensions of the NEO-FFI. T-tests were conducted to assess differences between hemodialysis patients and the general adult population in Japan as well as differences among gender, age, employment, duration of hemodialysis, and complications. These results were subsequently used to assess the characteristics of personality types using anova. The relationship between personality types and demographic characteristics was assessed using the χ2-test. For all statistical analyses, differences were considered significant at P < 0.05. All analyses were conducted using the SPSS statistical package version 13.0 (SPSS Inc., Chicago, IL, USA).
Selected patient characteristics are summarized in Table 1. The patients' ages ranged from 19 to 90 years (mean, 58 years and 3 months), the duration of hemodialysis ranged from 1 month to 27 years and 6 months (mean, 6 years and 7 months), the percentage of males in the sample was 56.5%, and the percentage of working persons (including farmers and the self-employed) was 22.2%. Percentages of patients with complications were as follows: diabetes mellitus 25.2%, retinopathy 22.2%, diabetes mellitus with retinopathy 15.4%, cardiac disease 20.4%, diabetes mellitus with cardiac disease 7.1%, hyperparathyroidism 15.9%, and cerebral apoplexy 7.8%.
Table 1. Demographic characteristics of hemodialysis patients
n = 608
Mean ± SD (years)
58.3 ± 12.8
Duration of hemodialysis
Mean ± SD (years)
6.7 ± 5.7
Diabetes mellitus with retinopathy
Diabetes mellitus with hyperparathyroidism
Diabetes mellitus with cardiac disease
Cardiac disease with hyperparathyroidism
Diabetes mellitus with cerebral apoplexy
Cardiac disease with cerebral apoplexy
Studies were conducted after providing sufficient written explanation to the patients regarding the purpose of the studies and the protection of personal information. The authors maintained strict control over the collected data to prevent disclosure of confidential information.
Personality of the hemodialysis patients based on the Neuroticism, Extroversion, Openness–Five Factor Inventory
The 60 items of the NEO-FFI demonstrated high internal consistency with a Cronbach's alpha of 0.71. Table 2 shows the correlations among the five dimensions of the NEO-FFI. Neuroticism was negatively correlated with extroversion (r = −0.218, P = 0.0001) and agreeableness (r = −0.342, P = 0.0001). Extroversion was positively correlated with agreeableness (r = 0.247, P = 0.0001) and conscientiousness (r = 0.310, P =0.0001), and agreeableness was positively correlated with conscientiousness (r = 0.271, P = 0.0001). However, all correlation coefficients were relatively low despite the significant results.
Table 2. Correlations among the five dimensions of the Neuroticism, Extroversion, Openness–Five Factor Inventory (n = 608)
Table 3 shows the comparisons between hemodialysis patients and the general Japanese population across the five dimensions of the NEO-FFI;16 hemodialysis patients scored significantly lower for extroversion (t = 7.368, d.f. = 535, P = 0.0001), openness (t = 15.396, d.f. = 498, P = 0.0001), agreeableness (t = 7.254, d.f. =507, P = 0.0001) and conscientiousness (t = 7.002, d.f. =528, P = 0.0001), but not for neuroticism.
Table 3. Differences between hemodialysis patients and the general Japanese population across the five dimensions of the Neuroticism, Extroversion, Openness–Five Factor Inventory
In terms of relationships with patient backgrounds (Table 4), the neuroticism score was lower in patients 65 years of age or older (t = 2.174, d.f. = 213, P = 0.031). The scores for extroversion (t = 2.383, d.f. = 165, P = 0.018) and conscientiousness (t = 2.813, d.f. = 171, P = 0.005) were higher in employed patients, and score for openness was higher in patients who were less than 65 years of age (t = 4.225, d.f. = 232, P = 0.0001) and who were employed (t = 3.098, d.f. = 163, P = 0.002). The agreeableness score was higher in females (t = 3.230, d.f. = 352, P = 0.001).
Table 4. Differences in the five dimensions of the Neuroticism, Extroversion, Openness–Five Factor Inventory by gender, age, employment, and duration hemodialysis
T-test was applied. * P < 0.05, ** P < 0.01, *** P < 0.001.
The differences in patients with and without comorbidities were examined using a paired t-test of the five-dimensional average of personality (Table 5). The neuroticism score was significantly higher in patients with hyperparathyroidism (t = 2.322, d.f. = 322, P =0.021), while the extroversion score was significantly lower in patients with cardiac disease (t = 2.703, d.f =155, 110, P = 0.008) or cerebral embolism (t = 2.715, d.f. = 32, 458, P = 0.011). The openness score in patients with diabetes was significantly lower (t = 3.078, d.f. =218, 105, P = 0.002), but it was significantly higher in patients with retinopathy (t = 2.254, d.f. = 160, 982, P = 0.026) or hyperparathyroidism (t = 2.724, d.f. = 89, 349, P = 0.008).
Table 5. Differences in the five dimensions of the Neuroticism, Extroversion, Openness–Five Factor Inventory by complications
T-test was applied. * P < 0.05, ** P < 0.01, *** P < 0.001.
Personality types of the hemodialysis patients based on the Neuroticism, Extroversion, Openness–Five Factor Inventory
Cluster analysis included 381 subjects who had complete data for all items of the NEO-FFI. Personality types were classified into four categories, which was the maximum number that enabled the characteristics of each dimension to be distinguished by type. Each category was named on the basis of the characteristics of the five dimensions. One-way anova showed that differences in personality types were statistically significant for neuroticism (F3,377 = 124.553, P = 0.0001), extroversion (F3,377 = 84.195, P = 0.0001), openness (F3,377 = 12.066, P = 0.0001), agreeableness (F3,377 =78.943, P = 0.0001), and conscientiousness (F3,377 =98.578, P = 0.0001). Post-hoc multiple comparisons among the personality types were conducted, as shown in Fig. 1.
1Among the agreeable type (22.6%), agreeableness was higher than the other three personality types (P = 0.0001), as expected. Conscientiousness was higher than the submissive type (P = 0.0001) andthe sensitive type (P = 0.0001). Neuroticism was lowest among the personality types (P = 0.0001).
2Among the submissive type (22.0%), conscientiousness was lowest compared to the other personality types (P = 0.0001).
3Among the sensitive type (21.5%), as expected, neuroticism was the highest (P = 0.0001), but extroversion and agreeableness were lower than the other personality types (P = 0.0001). Openness was lower than the balanced type (P = 0.0001).
4Among the balanced type (33.9%), openness was higher than the other personality types (P = 0.011), but the five dimensions were all within the mean range.
Table 6 reveals a notable relationship between personality type and age. There was a large number of agreeable type and a small number of sensitive type among patients 65 years of age or older (χ2 = 11.722, d.f. = 3, P = 0.008).
Table 6. Personality types of hemodialysis patient by age
Personality types of hemodialysis patient
χ2-test was applied. F = 11.722, d.f. = 3, P = 0.008.
<65 years (n = 272)
≥65 years (n = 109)
Characteristics of hemodialysis patients in comparison with the general adult population
According to the NEO-PI-R study by Shimonaka et al. on correlations among the five dimensions of personality in the general Japanese adult population, extroversion and agreeableness were negatively correlated.16 However, this study found that hemodialysis patients were quite different from the general adult population, given that extroversion and agreeableness were positively correlated. The high agreeableness score among patients with high extroversion scores may be a result of their positive acceptance of a variety of difficulties associated with hemodialysis, as extroversion indicates activity and positive emotions. This study also showed that hemodialysis patients do not differ from the general adult population with regard to neuroticism, but the patients' scores on all other four dimensions were significantly lower. However, it cannot be generalized that neuroticism among hemodialysis patients is the same as the general adult population because, by type, they include persons with high neurotic tendencies with high psychological sensitivity and persons with agreeable tendencies who tend not to worry. It is important to note that among hemodialysis patients with lower scores on the other four dimensions, openness was especially lower in comparison with the general adult population. The fact that the openness score, which relates to curiosity, proactiveness, and creativity, is lower appears to indicate a variety of limitations in their lives, including the deterioration in their bodily functions.17
The tendency for female patients to have higher agreeableness scores is also true in the general Japanese female population,16 and likewise, neuroticism and openness scores are confirmed to be low in both aged hemodialysis patients and the general aged Japanese population.18 Therefore, gender and age do not appear to be unique features among hemodialysis patients.
In Japan, the population is aging rapidly. Depression and suicide among the elderly have become a problem.19 A relationship between advanced age, depression and high neuroticism has been reported.20–25 Nevertheless, the present findings did not show high neuroticism scores in the elderly, with only a small number of elderly patients of the sensitive type. These findings may be a result of low recognition of stress or an abandonment of their life by the elderly.24 Although the number of elderly patients of the sensitive type was small, the authors think that sensitive psychological care is necessary because persons with this type are likely to develop depression.19
A study of hemodialysis patients using the GHQ30 showed that scores for items measuring social dysfunction and suicidality-depression were higher in unemployed patients.26 Given the positive correlation found between employment and openness in this study, the authors surmise that employment among hemodialysis patients is significant in terms of giving meaning to their lives, despite apparent difficulties associated with work.
Personality characteristics associated with comorbidities
With regard to findings obtained with the use of the NEO-FFI, studies of mental disorders have reported that patients with schizophrenia or delusion have high scores in the neuroticism and extroversion dimensions,20 with especially high scores for extroversion in obsessive–compulsive neurosis patients.21
Vulnerability, which is a facet of neuroticism, has been reported as an index for complications of post-stroke depression.22 This study suggests that negative symptoms, such as vulnerability, influence neuroticism in hemodialysis patients with hyperparathyroidism. Furthermore, there is a negative correlation between drug compliance among depressed patients and extroversion, particularly with respect to activity.23 The current study also suggests that due to their lower extroversion, hemodialysis patients with cardiac disease or cerebral embolism tend to have negative psychological states. Although previous studies point to a correlation between ischemic heart disease and the angry-hostility feature of neuroticism,27 the authors might have failed to observe the same relationship possibly because the NEO-FFI includes only one angry-hostility item.
In patients with diseases other than mental disorders, a positive correlation has been shown between neuroticism and mortality among elderly patients,24 as well as a tendency for recalling negative memories among elderly patients with low extroversion scores.25 These findings suggest that neuroticism and extroversion are closely associated with mental conditions. The fact that patients with diabetes had lower openness scores and that patients with retinopathy or hyperparathyroidism had higher openness scores appear to suggest that bodily disadvantage may increase openness.
Personality types and coping style among hemodialysis patients
It may be meaningful to characterize the individual personality types of hemodialysis patients to provide better individualized mental care. Here, the authors describe the four personality types of hemodialysis patients and suggest the ways to provide care for each type.
Among the agreeable type, as expected, agreeableness was the strongest dimension. Extroversion and conscientiousness scores were also slightly high in this agreeable type. Fundamentally, it indicates an altruistic personality. The high extroversion score signified having a strong interest in many issues, being active and talkative, seeking excitement, and having an optimistic attitude. Persons with a high conscientiousness score were moralistic and trusted by other people. Moreover, because of low neuroticism, people of this agreeable type were mentally stable and able to cope calmly with very stressful situations. The openness score was slightly low, but the score for this dimension was generally low in dialysis patients.
The authors think that combined with the other characteristics of this type, these patients are easily able to adapt to dialysis life.
People of the agreeable type are psychologically independent, likely to have strong decision-making skills, and build favorable human relationships, therefore, the authors assume that they do not have difficulty in seeking advice. However, in order for these individuals to maintain a stable mental condition, care providers may be required to inform them that mental health care is readily available whenever requested, while encouraging their altruistic qualities.
The agreeable type was frequently seen among elderly patients. Pre-war norms had a great impact on the personality formation of the current elderly generation in Japan. At that time, the ability to adjust oneself to the values of the group to which one belonged, instead of insisting on one's rights or liberty, was a desirable virtue. The authors thought that the large number of altruistic and agreeable types among the elderly patients was as a result of the characteristics of this generation.
Persons with agreeable-type personalities are easily able to maintain self-discipline and successfully self-manage their conditions. Nonetheless, for the elderly, there are handicaps in terms of knowledge, understanding, capacity for action etc. They also have difficulty changing their habits and values. Therefore, because the evidence suggests that elderly people are more likely to follow the directions of health-care professionals and prefer tailored living arrangements, conventional living instructions should be provided.
Low conscientiousness does not mean that a person entirely lacks the capacity to act according to moral principles. Rather, it means they do not make a sufficient effort to achieve objectives. Other characteristics include a lack of self-assertiveness or strong interest in issues, an unwillingness to perform activities or reach goals, and a suspicion of other people.16 Therefore, dialysis patients of the submissive type tend to rely on specialists rather than acting on their own to cope with the disease; they even accept the fact that the disease has progressed as a result of their submissive nature.
A low level of goal orientation may make disease self-management difficult. Persons of the submissive type may not accumulate control methods from experience, as they are influenced by the directions given by specialists.10 Health-care professionals often miss changes in medical conditions because the patients do not tend to assert themselves. As a result, health-care professionals are oftentimes frustrated by the aggravation of the disease in submissive types due to this issue. Consequently, it is suggested that health-care professionals encourage patients to report their complaints and promote independence and self-discipline, while making patients aware that they primarily are responsible for control of their physical condition. To achieve this, explanations should be given to patients so they can obtain a sufficient understanding of their disease, and health-care professionals also need to be actively and continuously involved in the lives of their patients.
Persons with a high score for neuroticism cannot easily control their anger and are less able to cope with stress than other people.16 If extroversion is low, there is a strong sense of dependency. If people have low openness, they are conservative and do not show strong emotional reactions. If people have low agreeableness, they are self-centered and distrustful. In simple terms, these people are sensitive to stress, and their reactions tend to be introverted. A good aspect of the coping styles of patients of the sensitive type is that they get involved in the details of their treatment and decision-making. Consequently, health-care professionals must respect their attitude for engaging in treatment and provide them with accurate and honest explanations in order for them to make decisions.
In type classifications, an intermediate, ‘balanced’ type will sometimes be identified. In this type, all of the five dimensions had average values, and there were no notable characteristic coping styles compared with the other types. Consequently, there is insufficient information for consideration on the specific support required for patients of this type. Further studies are needed to identify what kind of coping styles are applied by them and what kind of care is needed for those falling into this category.
LIMITATIONS AND CLINICAL IMPLICATIONS
This study was able to categorize the personalities of dialysis patients into four types. In clinical practice, if a patient's personality type can be identified, it becomes possible to implement type-oriented methods for providing explanations to patients and obtaining their informed consent, as well as for getting involved in the lives of patients, and providing instructions on disease self-management. It is particularly important that the submissive and sensitive types should receive appropriate mental health care.
This study was supported by a Grant-in-Aid for Scientific Research from the Japanese Ministry of Education, Culture, Sports, Science and Technology of Japan (14572263).