This study is the first to report that PRISM, an indicator of suffering, can be used to assess three psychosocial factors associated with chronic pain. These three elements of IMMPACT  have been identified in clinical practice as important outcomes in chronic pain management. We found that SIS is defined by these three factors, showing its utility as a simple visual evaluation method for the quick assessment of patient suffering by medical staff engaged in the treatment of chronic pain, e.g. physical therapists, occupational therapists, orthopedic surgeons, physicians, nurses, as well as psychologists and psychiatrists. Furthermore, we have shown for the first time that SMcS and SSoS are useful as methods for evaluating the interpersonal relationships of patients with chronic pain.
SIS of PRISM as an integrative tool
The SIS of patients with chronic pain in this study showed a significant correlation with 10 of the 21 pain-related subscales. Factor analysis of these scales extracted three factors: “Life interference”, “Negative affects”, and “Pain intensity”. The correlation coefficients for the SIS and the factor scores of these factors were significant.
The above pain-related aspects are considered to be elements corresponding to pain, physical functioning, and emotional functioning, which are reported to be important factors in IMMPACT . Further investigation is needed to clarify if or how the other three domains (participant rating of improvement and satisfaction with treatment; symptoms and adverse events; and participant disposition) are related to the PRISM variables.
This study yielded results consistent with previous PRISM validation studies [11, 12]. In them, the most consistent and significant negative correlation of SIS is reported to be depression and pain. Unexpectedly, in some cases, depression and health-related quality of life did not correlate with SIS. Suffering due to illness is thought to be influenced by numerous variables; however, none of the variables measure suffering directly, thus the correlations with suffering can be expected to be significant, but modest [11, 12]. Medical staff can intuitively understand the status of their patients with chronic pain when they see the PRISM image. Therefore, we believe that it is a useful, integrative, visualized measure that reflects many factors at the same time.
A study by Kassardjian et al.  examining the association between PRISM and psychosocial factors associated with the medical condition of patients with chronic pain showed a significant relation between SIS and pain sensation, physical function, and mental state. The results of the present study are consistent with their results. Although, their study showed a significant negative relation between pain catastrophizing and SIS, the current study did not. In the current study, the PRISM task measured ‘my illness’, whereas Kassardjian et al. measured ‘my pain’. This methodological difference may be responsible for the different results. It is possible that our patients are highly alexithymic: they may be aware of the distress from pain, but may not be aware of their catastrophizing. It is also possible that their pain behaviors may be being used to attract the attention of others or to avoid aversive interpersonal relations, which increases their catastrophizing. Due to these confounding factors, the two variables may not have a linear relation.
SMcS and SSoS as indicators of interpersonal relationships
In response to our supportive and empathetic psychotherapy, the position of medical care and significant others on PRISM-KV changed from admission to discharge. Both discs were closer to the discs representing the participants themselves (Self) after treatment than before treatment. Kassardjian et al.  showed that better relationships with patients exist when the partner and family on PRISM are placed closer to themselves. Prior to this study, no attempts have been made to put feelings about medical care on PRISM. Of the four comments on SMcS, all clearly expressed a change in their impression of their doctors, which indicates to us that the SMcS reflects their interpersonal relationship with medical care. The participants of this study showed that their relationship with medical staff members changed for the better and that they considered the staff members more reliable. It was also shown that inpatient treatment improved the relationship with significant others. Considering that our inpatient treatment was centered on supportive psychotherapy, it is not surprising that the patient/therapist relationship was reflected in the distance between medical care and self on PRISM-KV. The shorter distances reflected a better relationship between the patient and the therapist, and there is a possibility that experiencing intimacy with someone in a hospital influences the relationship between the patient and their significant others. Our data do not show a correlation between ΔSMcS and ΔSSoS, so the involvement of other confounding factors, i.e. interpersonal relationships with other patients, must be examined in future studies.
We previously reported that patients with chronic pain admitted to the Department of Psychosomatic Medicine had perceived lower care, higher overprotection, and affectionless control-type care from their parents at an early age than did a painless control group . It has also been suggested that relationships with significant others are strongly associated with pathology . Patients treated with a patient-oriented coping skill approach with spousal support have been reported to benefit more from treatment than did patients treated with a patient-only coping skill approach . Our patients were asked “Why do you feel this person is important to you?” after placing the disc of significant others. We feel that our results show that our patients place great importance to their interpersonal relationships. Improvement of relationships with significant others by patients with chronic pain is an important treatment step. This is the first study to show that this modified PRISM can be used to evaluate such changes in interpersonal relationships.
This study did not show significant change in the correlation of SIS with inpatient treatment. Previous longitudinal studies of PRISM report a sensitive response of SIS to treatment [12, 27,28,29]. In contrast, other reports did not reflect the effectiveness of treatment [30, 31]. Gielissen et al.  reported that the position of a cancer disc did not change despite successful treatment of fatigue in cancer patients. Töndury et al.  showed that patients with chronic urticaria showed no change in SIS despite improved symptoms and QOL.
The tertiary medical facility inpatient management of the patients of this study focused on psychosomatic assessment and the establishment of a therapeutic relationship, which may be the reason there was little change in pain suffering. To our knowledge, no longitudinal study of SIS in chronic pain has yet been done. Further investigation is needed to determine if successful psychosomatic interventions can change the SIS in chronic pain patients.
This study has the following limitations. First, there were only 72 participants, and only for 31 of them were we able to examine the effectiveness of treatment. There may be some selection bias because not all subjects could be included in the analysis. To generalize the results, it will be necessary to compare the change from before to after treatment for all consecutive participants. Second, a more detailed understanding of the properties of medical care and significant others when taken up as PRISM variables is needed. The selection of significant others was made by the PRISM evaluator, but it would be better if the patients were to do it themselves. Strategic examinations are needed on what factors are involved in the change of the distance of SSoS on PRISM, such as support for treatment and a change of partner. Third, we only applied qualitative analysis to determine the relationship with the medical care staff or significant others. Further investigation using a questionnaire on the relationship directly with various members of the medical care staff or significant others is needed to clarify that the distance actually reflects interpersonal relationships.
Despite these limitations, we found our evaluation method based on PRISM to be useful in the evaluation of the suffering of patients with chronic pain. Our investigation sheds light on the possibility that this modified PRISM can be used to assess the improvement of patient-therapist and patient-significant other relationships in response to supportive and empathic psychotherapy.