Factors associated with the persistence of medically unexplained symptoms in later life
van Driel-de Jong, Dorine
DOI:
10.33612/diss.136429372
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Publication date: 2020
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van Driel-de Jong, D. (2020). Factors associated with the persistence of medically unexplained symptoms in later life. University of Groningen. https://doi.org/10.33612/diss.136429372
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Summary and general discussion
Introduction
Healthcare providers tend to consider patients with persisting complaints of medically unexplained symptoms (MUS) difficult. Especially older patients often remain deprived of appropriate diagnoses and evidence-based treatment because of a lack of knowledge and interest in the phenomenon in this age group. The overall aim of the research presented in this thesis was twofold: we first wished to expand our knowledge about the factors associated with the persistence of MUS occurring in later life and secondly to use any new insights to inform cognitive behavioural therapy (CBT) for MUS to help treat older patients in particular. This led us to formulate the following three research questions:
1. How can we assess MUS in later life (Chapter 2)?
2. Which factors are associated with the persistence of MUS in older patients (Chapters 3, 4,
5, and 6)?
3. What is the feasibility of internet-based CBT for older patients with MUS (Chapters 7
and 8)?
Summary of the findings
In the final chapter of this thesis the most salient findings of the studies reported on are summarized and placed in a broader perspective, with limitations and strengths being discussed, and recommendations for clinical practice, education, and research proposed.
In the general introduction we introduced John who, at age 79, had been suffering from a “bad” feeling in his right shoulder for quite some time, which had a major impact on his daily life. In the light of the factors we described that are typically associated with the persistence of such MUS, the story below illustrates some of the findings and topics for further discussion our research yielded.
A case description (part 2)
Together with a psychotherapist, John learned to look for reasons that prevented him from feeling better to help him improve his daily functioning and regain quality of life. This joint exploration uncovered several issues that severely affected his daily life
(Chapter 4). John mostly felt sad, slept a lot, and his physical condition kept declining.
He was mourning the loss of relatives, avoided contact with remaining family members and friends, and preferred to stay at home most days. Also, John was very disappointed in doctors and felt they just left him to deal with things on his own. He completed the newly developed ICQ-plus, the Illness Cognition Questionnaire for older patients (Chapter 5), which showed he scored especially high on helplessness (e.g. ‘Because of my illness, I miss the things I like to do most’), catastrophizing (e.g. ‘I worry about how my physical
symptoms will develop in the future’), and avoidance (e.g. ‘By avoiding pressure my physical problem is reduced’). Based on these results, he and his therapist decided on a set of treatment goals, with going out to visit his children again and restoring his relationship with his GP being two such goals. He tried an internet-based CBT program (Chapter 7) but quickly quit because he found it too complicated, (Chapter 8) causing him too much stress and anxiety. The treatment that then toke place, consisted of 10 sessions of group CBT. Routine outcome monitoring (ROM) showed that both John’s quality of life and depression had greatly improved (Chapter 3). Even though the feeling in his shoulder was still there, it now affects his life far less. He also has a good relationship with his care providers who now all follow the same treatment plan. He appreciates his renewed visits to his GP because he keeps an ‘overview of things’ for him.
How can we assess MUS in later life?
Our first research question was addressed in the study described in Chapter 2. With the introduction of the DSM-5, the DSM-IV-TR section on somatoform disorders was replaced by a new classification: somatic symptom and related disorders 1. Limiting ourselves to our topic, the most important change in the diagnosis of somatic symptom disorders (SSDs) was a shift in focus, which now is on so-called positive criteria, where signs and symptoms should indicate that the physical symptom(s) are associated with significant distress and impairment as well as with dysfunctional thoughts, feelings, and behaviours. This contrasts with the
DSM-IV-TR description of somatoform disorders in which the absence of a medical explanation
for the somatic symptoms was core to the diagnosis. Although the SSD classification might aid the diagnostic process in both primary and specialized (somatic) healthcare, the criteria do not necessarily capture all patients burdened by MUS. Irrespective of the new DSM classification, MUS consistently leads to psychological distress, a lower quality of life (QoL), and increased medical consumption2, 3. In Chapter 2 we argued that the assessment of MUS in older adults is challenging due to the somatic multimorbidity so common in this age group, which threatens the validity of somatization questionnaires. In a previous systematic review of 40 questionnaires, the Patient Health Questionnaire (PHQ-15) and the somatization subscale of the Symptom Checklist 90-item version (SCL-90 SOM) were recommended for usage in large-scale studies 4. While both scales may indeed identify physical symptoms that in younger individuals frequently remain unexplained, in older persons these symptoms may more often be related to somatic diseases. To establish whether in older patients the assessment of MUS is more complex than generally assumed, we adopted two approaches. We first looked at correlations of the recommended PHQ-15 and SCL-90 SOM scales with proxies of somatisation, namely the presence of a somatoform disorder as determined with a semi-structured psychiatric interview and health anxiety as gauged with the Whitely Index, as well as with the objective somatic
with Unexplained Symptoms) studies, we found that PHQ-15 and SCL-90 SOM outcomes obtained in the two older age groups correlated with both somatisation proxies as well as with the somatic-disease-burden. This indicates that somatic comorbidity indeed influences the scores on the PHQ-15 and SCL-90 SOM, rendering both scales less valid to assess somatization in older adults. Next, we performed a systematic review of the literature to evaluate existing questionnaires designed to detect and monitor the severity of MUS. A total of 46 question-naires were identified and evaluated for their suitability in older populations, recording (the number of) items that either are not relevant for older adults (e.g. menstrual symptoms), those that overlap with common geriatric syndromes, the availability of normative data for and the scales’ use in older populations. None of the scales met our a-priori suitability criteria. The main problem was their limited use in studies of older patients. Only 8 of the 46 (17%) questionnaires had normative data for older age groups, with only one having been specifically validated in an older sample, and only 20 (43%) having been used at least once in an older population. Moreover, a median of 25% of items per scale were irrelevant for older persons or overlapping with common geriatric syndromes (range: 0-87%).
Evidently, reliability and validation studies in older populations are warranted especially in view of other typical differences between younger and older respondents. For example, compared to their younger counterparts, older persons are more inclined to give socially desirable answers5, while they also show more non-response and a tendency to give incon-sistent answers to health-related themes6. Based on our findings and the available data on the assessment instruments we evaluated, when studying MUS in older persons, we would still recommend the SCL-90 SOM and PHQ-15 for population-based studies despite their limitations, the Freiburg Complaint list and the somatisation subscale of the 53-item Brief Symptom Inventory for studies in primary-care settings, and finally the Schedule for Evaluating Persistent Symptoms (SEPS) and Somatic Symptoms Experiences Questionnaire (SSEQ) for monitoring studies.
Which factors are associated with the persistence of MUS in older patients?
As to our second research question, we found clear evidence that psychological distress and psychiatric comorbidity are associated with the persistence of MUS. Examining the psychiatric characteristics of 118 older patients with MUS and 154 age peers with MES in our OPUS study described in Chapter 3, we found that the patients with MUS reported higher levels of psychological distress and hypochondriasis compared to the patients with MES, irrespective of the healthcare setting they were treated in. However, this was not reflected by a significantly higher prevalence of psychiatric disorders, other than somatoform disorders (DSM-IV-TR classification criteria). When adjusted for age, sex, and level of education, there was hardly any difference between the MUS and MES groups, which finding was not in line with our expectations as we had hypothesised that patients with MUS would show more psychiatric comorbidity based on the exceptionally high prevalence rates found in our pilot study 7 and the findings derived from earlier studies conducted in populations receiving treatment in general practice and specialized care 8,9. Moreover, earlier findings had shown that health- related QoL was lower in patients with MUS than it was in those with MES 10, 11, as was their
functional health status12, 3, factors that are often associated with psychiatric comorbidity in MUS 13. The fact that older patients with MUS experience more psychological distress but ‘average’ levels of psychiatric comorbidity (as defined by the DSM-5) might imply a high prevalence of subthreshold psychiatric issues. If true, health professionals need to be alert for such subclinical mood and anxiety symptoms in patients with late-life MUS 14 since these generally have similar negative effects on Qol and functional impairment as the full-blown disorders 15. Another explanation for the average psychiatric comorbidity in MUS is offered by who, showed that, although levels were higher in patients suffering from MUS alone 9, they were not elevated or less so in patients presenting with both MUS and MES. Since older adults often suffer from unexplained, partly explained as well as explained somatic symptoms 16, this would then account for the lower levels of concurrent (DSM-5-defined) psychiatric comorbidity. Other results from the OPUS study indicated that psychological distress and psychiatric comorbidity are associated with a lower health-related QoL2. This negative effect is especially described for concurrent multiple comorbid psychiatric disorders. Still, this does not preclude psychological treatment. Several studies suggest that targeted CBT can be successful even in patients with MUS showing high levels of Axis-I and Axis-II comorbidity 17, 18.
Recent MUS treatment studies accordingly stress the importance of an additional treatment focus on comorbidity19. Then again, this raises the question which symptoms should be addressed first, but asking this question immediately suggests that MUS, anxiety, and depression are separate entities whereas research has shown they are overlapping constructs 20. Rather, for successful treatment, it is proposed to adopt a multidisciplinary approach to thus address all aspects of MUS simultaneously 8, 21, 22. However, when the anxiety and depressive symptoms are so severe that they are likely to interfere with a psychological intervention, their initial treatment may be warranted to attain the necessary flexibility for CBT 23.
In the study reported in Chapter 4 we compared the contributing factors of MUS in 160 patients with MUS (aged between 18 and 91 years) reported during a semi-structured interview with the main clusters of MUS-perpetuating factors from the perspective of clinicians24 and found them to coincide to a high degree, justifying the conclusion that patients and clinicians agree on which factors are involved in MUS. This unanimity is in contrast to earlier studies that stress that patients and professionals often have no common formulation of the problem or shared problem definition, nor a shared symptom-management plan 22, 25, 26. It needs to be noted, however, that the consensus as to the contributing factors of MUS does not (necessarily) imply that both parties share views on which of these individual factors have become locked in a vicious cycle, leading to symptom maintenance. This underscores the need to make a personalised inventory of what factors contribute to the continuation of the symptoms 27. We further concluded that while sex- and age-related differences in mentioned factors were minimal, compared to younger patients, older patients (≥65 years) reported more problems concerning ‘dysfunctional interactions with friends and relatives’ and ‘relationships with healthcare professionals’ but fewer problems concerning ‘fulfilling roles’, ‘making unrealistic
demands on yourself’ and ‘difficulty perceiving and interpreting emotions and physical processes’. But what might explain these notable age-specific differences? It has been suggested that older patients are better at interpreting physical symptoms and bodily sensations because they have had more experiences with both 28, 29. Additionally, patients with MUS tend to have an increasingly positive attitude towards physical health with increasing age 30, 31, which could explain why they report fewer psychological problems in the later stages of life. More problems with more ‘social’ themes may then result from an anxiety associated with the fear of becoming increasingly dependent on others, with anxiety or depression associated with being (more and more) dependent, or due to more frequent experiences with the loss of relatives or close friends32.
The impact of dependency was also supported by the findings of the study in Chapter 5, which showed that catastrophic cognitions, among which were the fear of dependence, were prominent in older patients with MUS. Having interviewed 21 patients, we identified 134 different cognitions of which 62 could be classified within the three generic categories of the Illness Cognition Questionnaire (ICQ)33. The remaining 72 cognitions were not covered by the list and thus considered of interest for extension of the ICQ. These 72 cognitions were translated into 26 new items. We developed and validated the extended ICQ (ICQ-plus) among 220 older persons with either MUS (n=83) or MES (n=137) in order to achieve an improved scale to assess illness cognitions in older patients. Factor analysis confirmed the three-factor structure of the original ICQ, i.e. helplessness, disease benefits, and acceptance. Four additional factors emerged from the analysis, covering cognitions on perseverance, illness anxiety, avoidance, and catastrophizing. These results showed us that the ICQ-plus was suitable for both patient groups. When we compared the MUS and MES groups, we noted that the patients with MUS scored significantly lower on acceptance and disease benefits, and higher on helplessness and illness anxiety. These new insights into typical perpetuating factors in later-life MUS may help us target interventions to (sub)groups, while the extended questionnaire may foster the identification of a patient’s most prominent adverse cognitions and thus add to the results obtained with interviews.
Subsequently, within the framework of the OPUS study described in Chapter 3, in the study presented in Chapter 6 we explored the natural course of patients’ illness cognitions and the determinants of change. An observational study of 154 older patients (≥ 60 years) suffering from physical symptoms who completed the Illness Cognition Scale-plus (ICQ-plus) at baseline and follow up as part of the OPUS study. While we found that the scores for the illness cognitions related to disease benefits, perseverance, illness anxiety, avoidance, and catastrophizing had not changed over time, for acceptance as well as helplessness they had only increased marginally, from which we inferred that illness cognitions show little change over time in older populations. Both psychological as well as somatic parameters were associated with cognition change. Psychopathology had an additional impact on the course of the illness cognitions: increases in psychopathology were associated with a decrease in disease benefits and an increase in illness anxiety over time.
As illness cognitions are closely associated with wellbeing and QoL, future research should examine which strategies are most effective in changing the maladaptive illness cognitions especially in the more vulnerable older patients. Since we found no differences in the illness cognitions of patients with MUS and MES, we venture that actively addressing maladaptive thoughts and behaviours to reduce their negative consequences is equally important for both patient groups.
What is the feasibility of Internet-delivered CBT for older patients with MUS?
The final question we addressed in the context of the research described in this thesis concerned the possibilities digital treatment formats could offer in changing perpetuating factors in older patients struggling with MUS. Could the current generation of older people receiving treatment for MUS in specialised mental-health facilities (additionally) benefit from internet-based CBT (iCBT)? Using a mixed-methods design, in the study presented in
Chapter 7 we explored the usability of our Dutch-language iCBT programme named ‘Master
Your Pain’ in terms of age, educational level, and digital health-literacy skills. The 32 patients aged between 22 and 75 years (mean age: 49.9 years) we recruited from two mental-health outpatient clinics experienced serious problems using the online program. On an operational, navigational, and search level, the participants struggled most with logging in, logging out, and finding specific modules of the intervention. Half encountered problems evaluating the relevance of treatment components and adding content to the programme to some extent. Some of the problems we observed mostly arose from the participants’ poor practical skills and could not be attributed to the design of the platform. Although the older patients who had more experience with computer use and the Internet proved able to use the iCBT program, they still struggled significantly more than did their younger counterparts. Age was moderately negatively related to the number of completed training tasks and moderately positively related to the number of problems encountered. These results are in line with previous studies 34, 35, which showed that the operational and navigational skills of older users were less well developed than they were in the younger users. These findings raised concerns as to the feasibility of the iCBT in older patients with MUS.
In the study reported in Chapter 8 we accordingly tested the willingness and ability to use our iCBT in 52 treatment-seeking psychiatric patients with a mean age of 72 years. Although worldwide but especially in Western countries more and more older persons are proficient at using the computer and the Internet, only 12 (23.1%) of our participants were willing to try the internet-based treatment and be part of our usability study. The reasons for refusing participation were lack of self-perceived computer skills, lack of treatment motivation, and mental or physical impairment. Those who did start with the iCBT program were hampered by their lack of digital skills, which mostly concerned general operating skills (e.g. problems using the keyboard and unfamiliarity with the functionality of tabs). Most also encountered problems with the program itself, in terms of sending a message via the mailbox at our clinic’s website, filling in a registration diary, selecting the correct assignment, and adequately applying the information provided, while all participants had problems logging out. Together,
these obstacles would prevent older patients from fully benefiting from our iCBT for MUS in its current form. Thus, to profit from online treatment, we recommend offering older patients a practice session, with a therapy assistant helping them to improve their operational skills and guide them through the program. Apart from such an introductory session, we should make iCBT more user-friendly especially for older users, while health professionals should also look at ways to improve the willingness of (older) patients to consider iCBT by promoting its benefits. In accordance with the recommendations of Griffiths et al.36, we finally suggest to train and treat older patients in the setting where they first seek treatment, i.e. primary care, as much as possible to minimise mobility problems37, 38.
Methodological considerations
In addition to the study-specific methodological considerations we presented, there are several general, overarching points that merit discussion.
A first observation is that the age ranges differed for the various cohorts. In the OPUS study we applied the cut-off of 60 years that is traditionally used for studies into late-life affective disorders 39. In the qualitative studies, however, the patients were recruited from clinical practice, where we adhered to a threshold age of 65 years. Nevertheless, we do not expect any noteworthy biases as a result of the differences in age range since in the OPUS study the focus was on the comparison of patients with MUS and MES and in the qualitative studies on differences between younger and older adults.
Studies in patients over the age of 65 years are rare because they tend to be excluded from clinical studies, which also holds for studies evaluating MUS and CBT 40, 41. To our knowledge, no randomised controlled studies have evaluated treatment strategies aimed at MUS in later life. The non-treatment studies that did include older patients with MUS often suffered from methodological problems, with their cross-sectional nature preventing firm conclusions and causal inferences from being drawn 42. Also, there is the inevitable loss of patients for follow-up in longitudinal studies monitoring older patients because of problems associated with increasing age and cognitive impairment 43. Moreover, the assessment instruments used have not been validated in older patients (Chapter 2), while the differences in definitions employed to delineate MUS also complicate the interpretation and comparison of the results reported, also due to changes in the classification of MUS, with the definition of somatoform disorders in the DSM-IV(-TR) being replaced by the DSM-5 classification of somatic symptom and related disorders, involving a clear shift of focus in the diagnostic criteria.
Finally, although we studied the biological, psychological, cognitive, and social factors associated with the persistence of MUS, which we derived from the theoretical model proposed by Deary et al.44 (Chapter 4), it needs to be noted that, while the experience of disease is at least partly determined by a patient’s cultural context, the Deary et al. model ignores cultural aspects that may play a role in MUS 45, 46.
The research described in this thesis included studies with both qualitative and quantitative designs. Below, we will summarise the strengths and limitations of the two methods.
The qualitative studies
Strengths
The qualitative research data on factors associated with the persistence of MUS presented in this thesis were collected using qualitative semi-structured interviews (Chapters 4 and 5) and systematic observations (Chapters 7 and 8), as is the standard for such investigations. The qualitative observational studies reported in Chapter 7 and Chapter 8 used a mixed-methods design to explore the usability of our dedicated iCBT program called ‘Master Your Pain’ in older patients with MUS or MES. In the performance tasks, participants were asked to vocalise their thoughts by thinking aloud. With this verbal-reporting technique we sought to gain insight into the patient’s personal decision-making and problem-solving strategies. Verbal reporting has been shown to be a valid method in observational research 47 and increases a study’s reliability 48.
Our analysis of the literature on the assessment of somatization and MUS in older patients, which revealed the need for a more tailored, validated scale, was based on an extensive and systematic search procedure to identify relevant papers 49 and a systematic review of all self-report instruments reported on. Two health professionals independently coded the usability of the self-report questionnaires using criteria derived from previous studies to identify 1) the number of items not applicable for older adults and those somatic symptoms that in older persons usually reflect somatic disease burden, 2) the presence of standardized scores (normative data) for older populations, and 3) whether the instrument had already been applied in an older sample (Chapter 2).
Limitations
Qualitative research methods do not allow results obtained in relatively small samples to be generalized to larger populations. However, our research was designed as an in-depth exploration of the actual perceptions and behaviours of older patients with MUS seeking or receiving treatment in specialist mental-health care.
A known problem in qualitative research is observer bias, which means that we, as clinicians and researchers, are implicitly selective when we observe and describe patients or clinical phenomena 50. We have tried to avoid this bias by adopting multi-rater methods. In our studies of MUS-perpetuating factors (Chapter 4), illness cognitions (Chapter 5), and geriatric diseases
(Chapter 2). In addition, in the case of uncertainty or doubt, an independent rater or our expert
group was consulted to reach a decision or consensus, while we used multiple methods, where possible, to investigate the same phenomenon or variable, for instance by supplementing our interviews with questionnaires (Chapter 5).
The quantitative studies
The OPUS study was designed as a case-control study and included 272 older patients suffering from physical symptoms, of whom 118 were struggling with MUS and 154 with MES, to help us identify concurrent psychiatric characteristics (Chapter 3), validate illness cognitions
(Chapter 5) and delineate the course and determinants of change in the reported illness
cognitions (Chapter 6).
Strengths
To our knowledge, the OPUS study is the first to evaluate late-life MUS in a large cohort. As controls, we recruited same-age patients diagnosed with MES, which means that their physical symptoms were fully explained by the presence of at least one known chronic somatic disease. We, moreover, took care that the severity of the primary physical symptom was comparable in both patient groups, while taking into account that the chances of developing MES in later life increase with age. Further, we included patients from primary, secondary, and tertiary healthcare, thereby covering the entire spectrum of older patients seeking or receiving treatment for MUS (Chapter 3). In each setting, a GP or geriatrician examined the patient thoroughly, providing a comprehensive description of the (un)explained physical symptom(s). Another strong point of OPUS is that, as Deary et al.44 proposed in their model, we looked at biological, psychological, as well as social variables to attain as complete a picture of the factors associated with MUS in later life as possible.
Finally, we wish to mention our exploration of the natural course of illness cognitions in later-life MUS. Because older patients with MUS are often not referred for therapy, we were able to include patients whose cognitions had not been changed by treatment and investigate natural changes over time.
Limitations
Concerning the ICQ-plus (Chapter 5), we need to mention that in its development we only made an inventory of cognitions among MUS patients. Although we compared the ICQ-plus scores of patients with MUS and MES in the quantitative part of the study, we may have missed specific cognitions that are more typical of MES patients. Further, in our study on the course and determinants of cognitions change (Chapter 6), 35.9% of the participants dropped out prematurely, where, in general, drop-out rates between 20% and 30% are considered normal for studies with older persons 51. However, although at baseline the patients dropping out of our study had lower levels of cognitive functioning and education, they did not differ significantly from the completers on any of the baseline ICQ-subscale items. Finally, the range of determinants of the course of illness cognitions we analysed was limited. Other determinants, such as alexithymia 52 or negative life events 53 may also be relevant for their course and merit consideration in future studies.
Implications for practice
In the introduction we mentioned that MUS pose serious problems for both the patient and the health professionals involved. Previous studies have shown that a shared (biopsychosocial) explanation for MUS contributes to a better doctor-patient relationship 54. Such a shared explanation might provide a tool to meet unmet care needs, especially those of the older patients, and help improve their psycho-education 55. Here, our finding that the factors contributing
to later-life MUS that patients reported overlap with the typical perpetuating factors the therapists observed is promising in that this accord might aid the treatment. We think that this agreement about the factors playing a key role in the maintenance of MUS may benefit the patient in that (s)he feels that his/her goals are being addressed, while it helps motivate the therapist in his or her approach. Moreover, the conclusion that there is little difference in these factors between older and younger patients may also encourage therapists’ willingness to treat older patients. Knowledge of individual MUS-associated factors, such as included in the hierarchical problem ontology or in the ICQ-plus (see appendices), provides therapists with well-defined starting points for personalised treatment, where they can help modify individual maladaptive illness cognitions as these have been shown to be quite persistent over time 56, 57. Finally, in older patients somatic comorbidity and cognitive functioning warrant special attention since these are also associated with the maintenance of maladaptive illness cognitions over time.
Although dedicated iCBT offers possibilities for the treatment of MUS, older patients in specialized care often lack the required digital skills, which deficit might be solved by an initial training session. Nevertheless, with the feasibility of iCBT in older patients being limited as yet, clinical practice has to look for other solutions for older patients declining (face-to-face) psychological treatment or those unable to visit a specialist outpatient clinic (e.g. due to mobility problems). One such solution might be to offer targeted treatment in the setting in which patients with MUS first look for help, mostly a primary-care centre close to their homes 37, 38.
Implications for education
Psychologists and other health professionals involved in the management of MUS need to realise also older patients are entitled to effective treatment. Therapists must shake off their therapeutic nihilism and be convinced that they are doing meaningful work. They should be made aware of the similarities and differences between older and younger patients and between later-life MUS and MES. In older patients, comorbid somatic complaints can complicate the assessment and treatment of MUS, with the often complex mix of unexplained and explained symptoms requiring intense and well-integrated multidisciplinary care. Here, offering physicians, nurses, and psychologists collective training might be fruitful. In addition, since the role of social problems in the persistence of MUS in older patients is substantial, psychologists should pay attention to both psychological and social factors, such as loneliness, loss of independence, and the impact of the (increasingly frequent) loss of friends and relatives. To improve the assessment of the factors associated with the persistence of MUS in individual patients, therapists are recommended to use the 16 clusters and the ICQ-plus as informative starting points.
The discrepancy between the need for psychological therapy and the limited supply of therapy 58, and the disappointing findings with respect to the usability and feasibility of iCBT, argues for a greater focus on the older patient with MUS in the training of therapists.
Implications for future research
The focus of the research presented in this thesis was on MUS in later life. Given the clear need for effective treatment, an important question still to be answered here is whether it is possible to change maladaptive cognitions in older patients. On the one hand, several studies on the effectiveness of CBT in later life found positive results, especially in patients with affective disorders, including anxiety 59-61 and depression 62. On the other hand, some studies concluded that, compared to younger patients, adverse cognitions are more difficult to change in older patients 63, which may be explained by the age-related decline in abstract reasoning skills, executive functioning, and cognitive flexibility 64-66. Finding which type of intervention helps induce cognition change in older patients coping with MUS then is the next important topic on the research agenda. To effectively help older patients with persistent somatic symptoms, we need to tailor (existing) CBT programmes to individual patient profiles, including age e.g.67, and make treatment more accessible for this older population. Considering the age-specific obstacles for treatment, such as reduced mobility, and the limited availability of face-to-face CBT for older patients, expectations regarding e-health were high. However, the results of our feasibility study testing dedicated iCBT for older patients with MUS in specialized care were disappointing. Further research therefore needs to focus on the improvement of the accessibility, content, and means of implementation of both conventional and Internet-based CBT for patients with later-life MUS.
Conclusion
Both the older patient and the health professionals involved, and most particularly the therapist, experience problems with the assessment of the nature and the treatment of the impact of physical symptoms for which no medical diagnosis has been found. The results of the studies collected in this thesis have added to our knowledge on the various factors associated with the persistence of MUS in older patients, while offering tools to explore and quantify relevant factors. Besides the many similarities between older and younger patients struggling with MUS and those between patients presenting with either MUS or MES (or both), there are also meaningful differences. When, during the assessment and treatment of MUS in later life, attention is paid to specific age-related problems, there are no reasons to exclude older patients from treatment or research. To improve the clinical assessment and management of later-life MUS, therapist training and research need to be stepped up because the growing number of older adults with physical symptoms, be they explained or not, deserve our attention to help them improve their (daily) functioning and regain their quality of life.
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