Type, distribution, and frequency of psychological capacity disorders in patients with different somatic illnesses

Abstract

Purpose

Somatic illnesses are often accompanied by (psychological) capacity impairments which impact on everyday life and work. The question is whether different somatic illnesses are associated with different capacity impairments, and whether impairment is more severe in cases of comorbid mental disorders.

Materials and Methods

Patients with neurological (N = 318), cardiological (N = 307) and orthopedic illness (N = 311) with and without comorbid mental illness according to MINI were investigated in a rehabilitation hospital. Psychological capacity impairments were assessed with the Mini-ICF-APP observer rating.

Results

The "baseline rate" of capacity impairment in patients without mental illnesses was 40.7% in orthopedic, in 36% of cardiology patients (36.1%) and in 74.9% of neurology patients. Patients with additional comorbid mental disorders had stronger impairments than those without mental illness. The most heavily impaired group overall were neurology patients with comorbid mental illness.

Conclusions

Somatic patients also have psychological impairments; these are more pronounced in the case of comorbid mental illnesses. It should be clearly explored whether psychological symptoms and impairment are an expression of the somatic illness per se, or due to a comorbid mental illness. Rehabilitation diagnostics should consider capacity impairments routinely in order to make indications for capacity trainings or context adjustment.

Implications for Rehabilitation

• A relevant number of patients with chronic somatic illnesses have psychological capacity impairments, and these are even more pronounced in the case of comorbid mental illnesses.

• Patients with neurological illness have more severe capacity impairments than patients with cardiological and orthopedic illness.

• Rehabilitation should routinely use capacity diagnostics (Mini-ICF-APP), in order to make indications for capacity training or compensative context adjustment.

Keywords:

• Capacities
• ICF
• somatic
• mental health
• impairment

Introduction

Based on the bio-psycho-social model of illness and health, illnesses not only manifest in symptoms (e.g., weight loss, mood disturbances, loss of vitality), but can also be accompanied by the impairment of capacities (e.g., cannot follow a meeting, making mistakes in writing a letter) [1,2]. Psychological capacities, the so-called "soft skills," include different interaction and self-control skills. Capacity impairments regularly lead to life participation impairments (e.g., being unfit for work) [2]. Impairments in psychological capacities can be caused by training deficits, or by physical or mental illness [3,4]. Capacity impairments in the here investigated sense are illness-related impairments. Psychological capacity impairments have until now been described in patients with mental illness [2] and patients with comorbid somatic and mental illness [5]. Until now it is unclear whether patients with somatic illness but without mental illness suffer from psychological capacity impairments as well.

Psychological capacity impairments and somatic illness

Psychological capacity impairments may result from different illness symptoms and affect activities of daily live and work: For example, in a project employee the capacity endurance may be impaired due to concentration dysfunction (=symptom) and impact on job-relevant psychological capacities: When listening for three hours in a conference the employeés endurance deficit results in problems (e.g., missing important information), and in need for help (e.g., take more notes, ask for repetition), or may make the employee even unable to attend the conference for a whole day. The symptom concentration dysfunction may be due to different illnesses, e.g., a stroke (somatic illness), or depression (mental illness).

In different somatic illness groups, there might be different types or distribution of capacity impairments, due to different symptom pattern. In the following the three investigated illness groups, associated psychological symptoms, and their potential impact on capacity impairments are characterized:

Neurology

The most common (first diagnosis) neurological illness among people who have recently become disability pensioners include cerebrovascular diseases (33%), multiple sclerosis (16%), epilepsy (4%), idiopathic Parkinson’s syndrome (3%), and traumatic brain injury (3%) [4]. Particularly in the case of neurological illness, accompanying psychological symptoms/dysfunctions are often part of the (core) symptomatology. Cognitive deficits, language disorders (such as word-finding disorders), a lack of attention and concentration deficits typically occur in patients after a stroke or craniocerebral trauma, and are characteristic of neurological illness [6]. Additional problems and psychological symptom development must be taken into consideration. These can include sudden falls due to an unsteady gait, followed by psychological symptoms like fear of falling, but also depressive mood due to sudden (physical) limitations as a result of the disease. These psychological symptoms can be "healthy suffering" [7], i.e., mood problems or anxiety as a normal reaction to an acute illness, but not so severe to become a mental illness per se. Finally, there may also be manifest mental illnesses according to ICD-10 [8], such as depressive episodes, anxiety disorders, which occur independently and in parallel to the neurological illness. Independent of the cause or type, the described psychological symptoms may bring about capacity impairments, i.e., problems to carry out activities and fill out life roles.

Cardiology

The most common issues in cardiological rehabilitation include chronic ischemic heart disease/coronary heart disease (CHD), acute myocardial infarction, heart failure, cardiac arrhythmias, and the presence of cardiac or vascular implants or transplants [9]. Similar to neurology and mental health problems, also in cardiology different "psycho-somatic interaction" exist [10], e.g., anxiety-development after a heart infarction, or a person with an anxiety disorder becomes hyper-aroused when she feels their heart beating during a relaxation exercise. Interactions between heart and mental state are the core issue of psycho-cardiology and need phenomenological differential diagnostic.

Beside a cardiac illness, there may be before-existing mental illness (mostly depressive and anxiety disorders, adjustment or posttraumatic stress reaction after reanimation). Mental complaints can also appear as "healthy suffering", i.e., as a normal, temporary state in the disease process [3,7]. There can be development of hypochondriac anxiety after an acute cardiac event, e.g., fear of new heart attack, avoidance behavior, which may become so severe to justify the diagnosis of a mental illness. Psychological pseudo-symptoms are at risk for leading to false conclusion - these are symptom pattern that resemble a mental illness, but have a physical cause. For example, a state of exhaustion can be a symptom of heart failure and must not be confused with depression, whose symptom pattern also often includes feeling weak [3,7]. Independent from their etiology, such mental syndromes are of great importance because they often impair patients’ psychological capacities, activities and participation to an even greater extent than the heart disease itself [11].

Orthopedy

In orthopedic rehabilitation, the most common illnesses include Cox- and Gonarthrosis, often with the surgical use of a total endoprosthesis (TEP) as a consequence, intervertebral disc damage, spinal stenosis, and (chronic) back pain in general [9]. As with patients with neurological and cardiological illnesses, studies have also shown certain comorbidities with mental illness for these patients. Anxiety and affective syndromes seem to be the most common in this context [12,13]. About every third orthopedic rehabilitation patient has at least one mental illness [14], which is in line with general epidemiology [15]. Comorbidity with a mental illness is often a risk factor for a chronic course of the orthopedic illness [12] and, depending on contextual factors, often impairs work ability and social life. In particular, chronic pain, which, in addition to limited mobility, is one of the central symptoms of orthopedic illness, can significantly impair capacities and social participation [16].

Measurement of capacity impairments

The individual impact of capacity impairments on work and life participation depends on which capacities are required, and to what extent [17]. Performance problems due to capacity impairments can lead to sick leave and work disability. A world-wide known and established instrument to assess and describe psychological capacity impairments is the Mini-ICF-APP observer rating [18]. It covers the following capacities: adherence to regulations, the planning and structuring of tasks, flexibility, professional competency, making judgements, spontaneous activities, endurance, assertiveness, contact with others, group integration, dyadic relations, self-care, and mobility. Their degree of impairment can be assessed by taking into account the respective contextual requirements (e.g., work ability at a concrete workplace, or work ability on the general labor market, or participation in general social life).

Capacity impairments, as objectivated by the Mini-ICF-APP, have previously been studied in psychosomatic patients and patients with mental illnesses [e.g., 5,19–25]. There are until now hardly data on the frequency, type, and degree of capacity impairment in patients with somatic illness [5]. To address this, our study investigated patients with neurological, orthopedic and cardiological illnesses concerning psychological capacity impairments.

Research question

How often and in which way do patients with neurological, cardiological and orthopedic illness suffer from psychological capacity impairments?

Are there differences in capacity impairments in the three somatic indications (cardiology, neurology, orthopedy), and between patients with and without comorbid mental illnesses?

To gain data on the distribution and frequency of psychological capacity impairments in somatic rehabilitation patients is of great importance for the future design of psycho-diagnostic competencies in rehabilitation clinics, and treatment options for specific capacity trainings or compensation measures in cases of chronic capacity impairments.

Method

Setting and patients

The study was conducted in a German rehabilitation hospital (Brandenburgklinik, Michels Hospitals, Bernau, Germany). All patients (neurology, cardiology, orthopedy) were in a health status that enabled them to move freely in the hospital environment, participate in single and group treatments and in patient education seminars. We analyzed all patients who were in internationally typical employable age of 18-65 years.

Instruments

Psychological capacity impairments were measured with the Mini-ICF-APP (“Activities and Participation in Psychological Disorders according to the International Classification of Functioning, Disability and Health”), in German language [18]. The Mini-ICF-APP is an internationally validated observer rating instrument which covers the following capacity dimensions: adherence to regulations, the planning and structuring of tasks, flexibility, professional competency, making judgements, spontaneous activities, endurance, assertiveness, contact with others, group integration, dyadic relations, self-care, and mobility. Since determination of any capacity impairment always needs a reference context [18], the standard reference context was chosen as “Independent living and working in any job on the general labor market”. For each capacity dimension, illness-related impairments were explored from the patient in a face-to-face interview. Ratings of impairments were made for each capacity dimension, on a Likert scale: 0 = “no impairment” (standard expectations of the reference group are fulfilled), 1 = “mild impairment” (subjective problems, but no negative consequences), 2 = “moderate impairment” (problems with activities, which are observable and result in negative reactions from others), 3 = “significant impairment” (the person needs help from others), 4 = “severe impairment” (the person is unable to do what is required). The interviews have been done by two specially trained psychotherapists (one of them was the author D.N.) and have been regularly supervised by a behavior therapist with social medicine specialization (B.M.). Inter-rater reliability corresponded well in most cases (k=.401 to k=.892). In order to get a better understanding of the content of capacity impairments, patients were asked to give a report and examples on each. Content validity was thereby assured [23]. Cronbach’s Alpha of the Mini-ICF-APP in this present investigation is .820. The Mini-ICF-APP has been validated and translated internationally [e.g., 24,25] and is recommended for use in social medicine guidelines [26–28].

Mental illnesses according to DSM research criteria have been explored with the semi-structured International Neuropsychiatric Interview (MINI 4.4) [29]. Those patients who fulfilled the research criteria of any mental illness category according to MINI were categorized as mentally ill, and all others were categorized as not mentally ill. Somatic diagnoses and sociodemographic data were taken from routine case reports from the hospital. There were no data on illness severity available.

The prognostic work ability of the patients was assessed by the treating physicians in clinical routine. They had to give a statement whether patients were a) able to work less than three hours per day, or b) able to work three to six hours, or c) able to work more than six hours.

Statistical analysis

For group comparisons, either the Chi² test or the Welch ANOVA was applied. There was no variance homogeneity (checked by Levene tests), thus we chose the Welch ANOVA to evaluate the hypotheses. The fact that not all dimensions are normally distributed across groups (checked by QQ plots) seems unproblematic, because the (Welch) ANOVA reacts robustly to deviations from the normal distribution if the groups are not too small (at least ten cases per group) [30]. If the ANOVA has p-values lower than 0.05, then post- hoc-tests were performed to see which samples the differences reached significance between. To examine the influence of the factors of the somatic discipline (neurology, orthopedy, cardiology) and mental illness, we use an ANCOVA. We controlled for the variables of gender, age, and whether someone currently had a job.

We used pairwise (instead of listwise) exclusion, in order to work with as much data as possible. If there was missing data, the deviating sample size was indicated in the table. We assume that the missing values are random, so that there is no loss in the interpretability of the data. Since there is not a single hypothesis for each item of the Mini-ICF APP, the significance level was adjusted with Bonferroni correction in order to prevent effects of multiple testing (Table 4).

Ethics

The study was reviewed and approved by the ethics and data protection committee of the Technische Universität Braunschweig (number: D-2018-09). All participating patients gave their written informed consent.

Results

We investigated patients with neurological (n = 318 patients), orthopedic (n = 311), cardiac (n = 307) illnesses.

There were significantly more women in the neurological sample than in cardiology, which had the fewest women overall (Table 1). The orthopedic group included significantly more women than in the neurological and the cardiological sample. Patients with neurological diseases were on average younger than patients with cardiological or orthopedic illnesses.

Table 1. Characteristics of the investigated somatic rehabilitation patients.

	Neurology	Cardiology	Orthopedics	All	Significance in group comparison (Chi², Welch ANOVA, Post-Hoc-Tests)
Gender: Female	44.0% (n = 318)	29.0% (n = 307)	58.5% (n = 311)	43.9% (n = 936)	Chi²: p<.001**; Pairwise comparisons: Cvs.O: p<.05* Cvs.N: p<.05* Ovs.N: p<.05*
Age (M, SD)	52.53 (10.19) (n = 318)	54.66 (7.93) (n = 307)	54.12 (8.83) (n = 311)	53.75 (9.08) (n = 936)	Welch ANOVA: p=.013* Cvs.O: p>.999 Cvs.N: p=.010* Ovs.N: p=.082
Disability pension a) neither planned nor applied for b) planned c) applied for or in social court proceedings/litigation	a) 79.8% b)15.3% c) 4.9% (n = 307)	a) 87.9% b) 9.4% c) 2.6% (n = 307)	a) 86.8% b) 8.0% c) 5.1% (n = 311)	a) 84.9% b) 10.9% c) 4.2% (n = 925)	Chi²: p=.013* Pairwise comparisons: a) Cvs.O: p>.05 Cvs.N: p<.05* Ovs.N: p>.05 b) Cvs.O: p>.05 Cvs.N: p>.05 Ovs.N: p<.05* c) p>.05 in all cases
Presently employed	66.0% (n = 315)	82.7% (n = 307)	76.2% (n = 311)	74.9% (n = 933)	Chi²: p<.001** Pairwise comparisons: Cvs.O: p>.05 Cvs.N: p<.05* Ovs.N: p<.05*
Sick leave duration within the last 12 months, in weeks (M, SD) (N = 484; patients with any sick leave)	10.64 (15.83) (n = 126)	7.31(11.87) (n = 157)	11.96 (15.47) (n = 201)	10.11 (14.61) (n = 484)	Welch ANOVA: p=.005** Pairwise comparisons: Cvs.O: p=.008** Cvs.N: p=.168 Ovs.N: p>.999
Ability to work on the general labor market (according to discharge report) a) < 3h b) 3-6h c) >6h	a) 18.5% b) 12.0% c) 69.5% (n = 249)	a) 0.4% b) 0.8% c) 98.8% (n = 259)	a) 2.0% b) 2.0% c) 96% (n = 301)	a) 6.6% b) 4.7% c) 88.8% (n = 809)	Chi²: p<.001** Pairwise comparisons: a-c) Cvs.O: p>.05 Cvs.N: p<.05* Ovs.N: p<.05*

N: Neurology; O: Orthopedics; C: Cardiology. *p < .05, **p < .01. The different numbers of cases in some statistical analyses are due to partly missing values.

The number of patients who had either applied or planned to apply for disability pension was highest in the patients with neurological diseases, followed by patients with cardiological and orthopedic illnesses. Patients with cardiological illnesses were significantly more likely to have a job than patients with neurological illnesses. The patients with orthopedic illnesses reported the longest mean sick leave in the past year (12 weeks), followed by the patients with neurological (11 weeks) and cardiological illnesses (7 weeks). In the end of rehabilitation treatment, patients with neurological illnesses were more often certified for work abilities below three hours or between three and six hours (30%), than patients with orthopedic (4%) and cardiological illnesses (1.2%).

Patients with mental illnesses have more severe impairments in most capacities than non-mentally ill patients (Tables 2 and 4). 86.8% of the patients with mental illnesses have severe impairments (rating ≥2). This compares with only 48.5% for patients without mental illnesses.

Table 2. Capacity impairments in somatic rehabilitation inpatients considering the factor mental illness (yes/no) and the factor patient group (neurology, orthopedics, cardiology). Means (standard deviation) and percentages of patients with relevant capacity impairment are reported.

	Adherence to regulations M (SD) ≥ 2 [%]	Planning and structuring of tasks M (SD) ≥ 2 [%]	Flexibi-lity M (SD) ≥ 2 [%]	Professional competency M (SD) ≥ 2 [%]	Judgements M (SD) ≥ 2 [%]	Spontaneous activities M (SD) ≥ 2 [%]	Endurance M (SD) ≥ 2 [%]	Assertiveness M (SD) ≥ 2 [%]	Contact with others M (SD) ≥ 2 [%]	Group integration M (SD) ≥ 2 [%]	Dyadic relationships M (SD) ≥ 2 [%]	Self-care M (SD) ≥ 2 [%]	Mobility M (SD) ≥ 2 [%]	Globalrating (M, SD)	Patients with an impairment of ≥ 2 in at least one capacity dimension
Patients with mental illness	0.75 (1.18); 25.1% (n = 263)	0.64 (1.05); 22.0% (n = 264)	0.90 (1.17); 32.1% (n = 262)	0.58 (1.14); 18.9% (n = 265)	0.62 (1.13); 20.2% (n = 263)	0.86 (1.15); 28.1% (n = 263)	1.98 (1.48); 63.4% (n = 265)	0.66 (1.10); 23.0% (n = 265)	0.62 (1.05); 21.8% (n = 266)	0.63 (1.01); 22.6% (n = 265)	0.55 (1.09); 19.4% (n = 263)	0.36 (0.85); 13.2% (n = 265)	0.68 (1.13); 23.8% (n = 256)	0.76 (0.61) (n = 266)	86.8% (n = 242)
Patients without mental illness	0.29 (0.78); 8.7% (n = 665)	0.22 (0.66); 6.3% (n = 665)	0.31 (0.77); 9.8% (n = 662)	0.22 (0.70); 6.2% (n = 661)	0.18 (0.62); 5.6% (n = 666)	0.34 (0.76); 9.8% (n = 666)	1.04 (1.35); 33.6% (n = 664)	0.26 (0.73); 7.8% (n = 665)	0.16 (0.53); 4.7% (n = 666)	0.19 (0.58); 6.5% (n = 666)	0.18 (0.62); 5.9% (n = 665)	0.14 (0.55); 4.5% (n = 666)	0.17 (0.57); 5.5% (n = 650)	0.29 (0.40) (n = 667)	48.5% (n = 633)
Neurology	0.75 (1.18); 23.6% (n = 314)	0.62 (1.07); 20.1% (n = 314)	0.82 (1.18); 27.8% (n = 309)	0.69 (1.19); 21.3% (n = 310)	0.57 (1.09); 17.5% (n = 314)	0.65 (1.10); 18.8% (n = 313)	2.11 (1.52); 65.1% (n = 315)	0.61 (1.13); 20.0% (n = 315)	0.48 (0.97); 14.9% (n = 316)	0.42 (0.88); 14.0% (n = 315)	0.34 (0.85); 11.5% (n = 312)	0.40 (0.90); 14.0% (n = 315)	0.54 (1.03); 18.6% (n = 290)	0.70 (0.63) (n = 317)	80.9% (n = 262)
Orthopedics	0.28 (0.75); 10.0% (n = 309)	0.17 (0.54; 5.2% (n = 309)	0.34 (0.76); 11.3% (n = 309)	0.15 (0.56); 4.5% (n = 310)	0.13 (0.50); 3.9% (n = 309)	0.44 (0.83); 13.9% (n = 310)	0.78 (1.19); 26.9% (n = 309)	0.29 (0.69); 9.1% (n = 309)	0.19 (0.58); 7.1% (n = 310)	0.30 (0.72); 11.0% (n = 310)	0.31 (0.81); 11.0% (n = 310)	0.14 (0.51); 3.9% (n = 310)	0.25 (0.71); 8.7% (n = 310)	0.29 (0.37) (n = 310)	50.8% (n = 309)
Cardiology	0.23 (0.68); 6.2% (n = 305)	0.21 (0.64); 6.9% (n = 306)	0.27 (0.71); 9.2% (n = 306)	0.13 (0.53); 3.6% (n = 306)	0.21 (0.70); 7.5% (n = 306)	0.37 (0.77); 12.1% (n = 306)	1.02 (1.26); 33.8% (n = 305)	0.22 (0.64); 7.2% (n = 306)	0.19 (0.59); 6.5% (n = 306)	0.22 (0.65); 8.2% (n = 306)	0.21 (0.73); 6.5% (n = 306)	0.07 (0.37); 2.9% (n = 306)	0.15 (0.58); 5.2% (n = 306)	0.27 (0.36) (n = 306)	48.7% (n = 304)

The different numbers of cases in some statistical analyses are due to partly missing values.

Patients with neurological illness have, on average, more severe impairments in all 13 capacities than patients with orthopedic and cardiological illness, with little difference between the latter two groups (Tables 3 and 4). The proportion of patients with more severe impairments is also significantly higher in patients with neurological illness (overall: 80.9%, without mental illness: 74.9%, with mental illness: 93.1%) than patients with orthopedic (50.8%, 40.7%, 80.8%) and cardiological (48.7%, 36.1%, 85.7%) diseases. The most impaired capacity in all three groups is endurance, and the least impaired capacity is self-care.

Table 3. Capacity impairments for somatic rehabilitation inpatients with and without mental illness according to MINI. Means (standard deviation) and percentages of patients with relevant capacity impairment are reported.

	Adherence to regulations M (SD) ≥ 2 [%]	Planning and structuring of tasks M (SD) ≥ 2 [%]	Flexibi-lity M (SD) ≥ 2 [%]	Professional competency M (SD) ≥ 2 [%]	Judgements M (SD) ≥ 2 [%]	Spontaneous activities M (SD) ≥ 2 [%]	Endurance M (SD) ≥ 2 [%]	Assertiveness M (SD) ≥ 2 [%]	Contact with others M (SD) ≥ 2 [%]	Group integration M (SD) ≥ 2 [%]	Dyadic relationships M (SD) ≥ 2 [%]	Self-care M (SD) ≥ 2 [%]	Mobility M (SD) ≥ 2 [%]	Globalrating (M, SD)	Patients with an impairment of ≥ 2 in at least one dimension
Neurology with mental illness	0.97 (1.26) 30.6% (n = 108)	0.92 (1.21) 32.1% (n = 109)	1.20 (1.29) 42.1% (n = 107)	1.07 (1.41) 34.5% (n = 110)	0.99 (1.36) 31.5% (n = 108)	1.05 (1.29) 30.6% (n = 108)	2.50 (1.46) 74.5% (n = 110)	0.87 (1.29) 30.9% (n = 110)	0.80 (1.21) 25.2% (n = 111)	0.74 (1.10) 25.5% (n = 110)	0.56 (1.10) 20.4% (n = 108)	0.51 (1.02) 20.0% (n = 110)	0.91 (1.28) 30.7% (n = 101)	1.01 (0.67) (n = 111)	93.1% (n = 87)
Neurology without mental illness	0.63 (1.13) 19.9% (n = 206)	0.45 (0.95) 13.7% (n = 205)	0.62 (1.07) 20.3% (n = 202)	0.48 (1.00) 14.0% (n = 200)	0.35 (0.84) 10.2% (n = 206)	0.45 (0.92) 12.7% (n = 205)	1.90 (1.51) 60.0% (n = 205)	0.47 (1.01) 14.1% (n = 205)	0.31 (0.76) 9.3% (n = 205)	0.24 (0.67) 7.8% (n = 205)	0.23 (0.66) 6.9% (n = 204)	0.34 (0.82) 10.7% (n = 205)	0.34 (0.80) 12.2% (n = 189)	0.53 (0.53) (n = 206)	74.9% (n = 175)
Orthopedics with mental illness	0.62 (1.08) 23.1% (n = 78)	0.32 (0.78) 11.5% (n = 78)	0.76 (1.06) 26.9% (n = 78)	0.22 (0.64) 6.4% (n = 78)	0.22 (0.60) 6.4% (n = 78)	0.83 (1.05) 29.5% (n = 78)	1.37 (1.41) 47.4% (n = 78)	0.50 (0.83) 16.7% (n = 78)	0.49 (0.91) 19.2% (n = 78)	0.67 (1.00) 24.4% (n = 78)	0.62 (1.11) 21.8% (n = 78)	0.31 (0.74) 9.0% (n = 78)	0.60 (1.02) 23.1% (n = 78)	0.58 (0.48) (n = 78)	80.8% (n = 78)
Orthopedics without mental illness	0.17 (0.56) 5.6% (n = 231)	0.11 (0.42) 3.0% (n = 231)	0.20 (0.57) 6.1% (n = 231)	0.13 (0.54) 3.9% (n = 232)	0.10 (0.45) 3.0% (n = 231)	0.30 (0.69) 8.6% (n = 232)	0.58 (1.03) 19.9% (n = 231)	0.22 (0.62) 6.5% (n = 231)	0.09 (0.37) 3.0% (n = 232)	0.18 (0.54) 6.5% (n = 232)	0.21 (0.66) 7.3% (n = 232)	0.08 (0.39) 2.2% (n = 232)	0.13 (0.51) 3.9% (n = 232)	0.19 (0.27) (n = 232)	40.7% (n = 231)
Cardiology with mental illness	0.57 (1.11) 19.5% (n = 77)	0.53 (0.94) 18.2% (n = 77)	0.65 (1.01) 23.4% (n = 77)	0.26 (0.80) 9.1% (n = 77)	0.51 (1.03) 18.2% (n = 77)	0.64 (0.99) 23.4% (n = 77)	1.84 (1.33) 63.6% (n = 77)	0.53 (0.98) 18.2% (n = 77)	0.48 (0.91) 19.5% (n = 77)	0.44 (0.87) 16.9% (n = 77)	0.48 (1.06) 15.6% (n = 77)	0.19 (0.61) 7.8% (n = 77)	0.44 (0.95) 15.6% (n = 77)	0.58 (0.48) (n = 77)	85.7% (n = 77)
Cardiology without mental illness	0.11 (0.39) 1.8% (n = 228)	0.10 (0.46) 3.1% (n = 229)	0.15 (0.52) 4.4% (n = 229)	0.08 (0.38) 1.7% (n = 229)	0.11 (0.50) 3.9% (n = 229)	0.28 (0.66) 8.3% (n = 229)	0.74 (1.11) 23.7% (n = 228)	0.11 (0.43) 3.5% (n = 229)	0.09 (0.35) 2.2% (n = 229)	0.14 (0.54) 5.2% (n = 229)	0.12 (0.55) 3.5% (n = 229)	0.03 (0.24) 1.3% (n = 229)	0.06 (0.33) 1.7% (n = 229)	0.16 (0.24) (n = 229)	36.1% (n = 227)

The different numbers of cases in some statistical analyses are due to partly missing values.

Table 4. The results of a ANCOVA (HC3-method [40]) show the effects of the population and mental illness factors on the capacity impairments, controlled for the variables “gender female”, “age” and “presently employed”.

ANCOVA	Adherence to regulations	Planning and structuring of tasks	Flexibi-lity	Professional competency	Judgements	Spontaneous activities	Endurance	Assertiveness	Contact with others	Group integration	Dyadic relationships	Self-care	Mobilty
	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²	B, p, Eta²
Mental illness^a	−0.35, .247, .006	−0.46, .008**, .013	−0.57, .002**, .016	−0.61, <.001**, .018	−0.62, <.001**, .019	−0.62, <.001**, .021	−0.54, .003**, .010	−0.40, .078, .008	−0.50, .001**, .016	−0.48, <.001**, .019	−0.32, .065, .008	−0.18,>.999, .003	−0.57, <.001**, .018
Cardiology^b	−0.39, .351, .005	−0.37, .286, .006	−0.52, .039*, .010	−0.81, <.001**, .027	−0.44, .195, .006	−0.41, .208, .006	−0.57, .091, .008	−0.32, .832, .004	−0.32, .520, .005	−0.25, .936, .004	−0.05, >.999, .000	−0.29, .169, .007	−0.45, .091, .008
Orthopedics^b	−0.39, .338, .005	−0.62, <.001**,.019	−0.47, .091, .008	−0.89, <.001**, .035	−0.76, <.001**, .028	−0.24, >.999, .002	−1.14, <.001**, .030	−0.41, .117, .007	−0.31, .572, .004	−0.07, >.999, .000	0.09, >.999, .000	−0.22, >.999, .003	−0.35, .585, .004
Gender female	0.10, >.999, .003	0.09, >.999, .003	0.21, .007**, .013	0.08, >.999, .002	0.02, >.999, .000	0.04, >.999, .001	0.26, .039*, .009	0.18, .039*, .010	−0.10, .520, .005	−0.08, >.999, .003	−0.18, .006**, .013	0.07, >.999, .002	0.16, 0.52, .009
Age	−0.00, >.999, .000	.002, >.999, .001	−0.00, >.999, .000	0.01, >.999, .003	−0.01, .507, .005	0.00, >.999, .000	0.00, >.999, .000	−0.00, >.999, .001	0.00, >.999, .000	−0.00, >.999, .001	−0.00, >.999, .000	0.00, >.999, .000	0.00, >.999, .000
Presently employed	0.13, >.999, .003	0.16, .247, .006	0.03, >.999, .000	0.18, .221, .006	0.14, .598, .004	0.16, .481, .005	0.32, .039*, .009	0.12, >.999, .003	0.17, >.999, .007	0.07, <.001**, .029	0.25, .007**, .013	0.22, .004**, .014	0.20, .078, .008
No mental illness x Cardiology^c	−0.09, >.999, .000	0.06, >.999, .000	0.10, >.999, .000	0.46, .130, .007	0.24, >.999, .002	0.29, >.999, .003	−0.51, .494, .005	−0.03, >.999, .000	0.11, >.999, .000	0.21, >.999, .002	0.03, >.999, .000	0.00, >.999, .000	0.23, >.999, .002
No mental illness x Orthopedics^c	−0.07, >.999, .000	0.29, >.999, .003	0.03, >.999, .000	0.55, .026*, .011	0.54, .013*, .012	0.12, >.999, .000	−0.19, >.999, .001	0.15, >.999, .001	0.13, >.999, .001	.070, >.999, .000	−0.04, >.999, .000	−0.53, >.999, .000	0.14, >.999, .001

*p < .05, **p < .01.

^aReference category = no acute mental illness.

^bReference category = neurological patients.

^cReference categories = acute mental illness and neurological patients. All p-values are Bonferroni-corrected.

Discussion

Psychological capacity impairments occur in cardiology, neurology, and orthopedy

The data show that neurological, orthopedic, and cardiological illnesses without comorbid mental illness are regularly associated with impairments in psychological capacities. These in turn can have an impact on the patients’ participation and quality of life [e.g., 31–35].

The "baseline rate" of relevant capacity impairment (rating ≥ 2) in patients without mental illnesses differs a little between orthopedic (40.7%) and cardiology rehabilitation patients (36.1%) but is significantly lower than in patients with neurological illness (74.9%). An explanation may be the fact that neurological illnesses are naturally associated with accompanying psychological symptoms [5]. Strokes, craniocerebral trauma, aneurysms, etc., are also acute, life-threatening conditions and initially throw the affected person abruptly out of rhythm of their everyday life with inability to fulfill their general life activities even at home. Orthopedic rehabilitation patients, on the other hand, have often had a planned, non-life-threatening operations of hip or knee. The consequences of such treatments can be planned and thus might be less heavily interruptive. Cardiology includes some chronic illnesses with years of disease history (e.g., blood pressure dysfunctions, heart insufficiency), but also cases with acute conditions, such as myocardial infarctions.

Higher capacity impairments in patients with mental illness

Comorbid mental illnesses may exacerbate impairments [36], to be seen by increased rates of capacity impairments in 80 to >90% of the comorbid patients. The phenomenon that comorbid patients have strongest capacity impairments (followed by patients with mental illness, and lowest in patients with cardiac illness only) has also been found in a recent investigation in cardiology patients, in which patients gave self-ratings on their perceived capacity levels [37]. There are meanwhile complex care systems for patients with somatic and mental illness in which mental and somatic therapy approaches are individually tailored to the needs of each patient [38]. Such treatment settings have been established in form of psycho-cardiological, or psycho-oncology clinics, or others [39,40].

In all three patient groups, the capacity endurance is most severely affected. It can be assumed that pain and somatic impairments as such, but also a cognitive focus on the physical complaints, may be a specific barrier for enduringly fulfilling onés work and life duties, and present in reduced psychological endurance as well (e.g., needing more breaks, cancelling activities).

Mental illnesses in somatic patients

In the general population, about 30% of people suffer from any mental illness [15]. Compared to this, a slightly below-average rate can be seen in the here investigated cardiology (25.1%) and orthopedic sample (25.4%), but in the neurological group there was a slightly above-average rate (34.9%). Neurological illnesses are by their nature [6] associated with a stronger suffering from cognitive impairment and thus patients may report bad mood, irritation, and insufficiency: mental functioning is experienced as limited and deficient.

Limitations

Limitations of the present study are that we have only referred to clinical information on the type of neurological, cardiological und orthopedic illness, and have no information on the illness severity. It is possible that capacity impairments may be partly influenced by the severity of neurological, cardiological or orthopedic illness. However, patients were quite homogenous in their activity status being able to follow an inpatient rehabilitation treatment including basic mobility and group capacities.

The study was done in an inpatient rehabilitation setting, so results may be different in outpatients.

The type of mental illness, e.g., anxiety or mood disorder, was also not taken into account differentiated. The criterion for being categorized as mentally ill was fulfilling criteria of any mental illness according to the standardized research interview MINI. Mentally ill people who are currently symptom-free (as in the case of a recurrent depressive episode) could have been classified as healthy, other patients could have been categorized as mental ill although the symptoms were due to healthy suffering or by-symptoms of the somatic illness [40, 3, see the following methodological problems and diagnostic implications for further discussion].

Methodological problems of structured interviews

An important methodological problem of mental illness research diagnostic must be discussed in that respect: Simply counting symptoms, as is done in structured interviews like the MINI, is sufficient for research purposes, but does always not lead to clinically valid diagnosis of mental illness [3]. Such interviews come along with unavoidable methodological artefacts: patients may simply fulfill criteria of standardized research interviews, e.g., bad mood, irritation, concentration problems, sleep problems, but there is no full observation and exploration of the patients history. Thus, patients may fulfill the “mental illness criteria” by answering symptoms with “yes” in the interview, but they do not have a “real” mental illness [3]. Standardized research interviews can only count for symptoms, but they cannot consider the full history and observation of the patient as would be done in full clinical investigations.

Clinical implications

When describing and diagnosing illness and capacity impairments, there are two description levels: illness symptoms, and capacity impairments.

First, clinicians must - on the illness level - distinguish healthy suffering, comorbid mental illnesses, and symptoms of the somatic illness: Not every psychological complaint, e.g., anxiety or irritation, is a mental illness. Many patients show psychological complaints after acute events, such as short-term anxiety or worrying after a heart attack, which is “healthy suffering” as a reaction to the physical event [7]. Mostly the anxiety passes by when the physical state is cleared and improved. An “anxiety disorder” would be if the anxiety is long-lasting and impairing daily life of the patient. In case the mental illnesses already existed before the onset of the somatic illness, the somatic illness may trigger new episodes of the mental illness, or syndromes previously classified as subclinical may become more recognized and “diagnosed”.

Second, clinicians must describe capacity impairment: Capacity impairments can occur as a result from any of the above-described phenomena: from psychological by-symptoms of somatic illness, or from “healthy” mental disturbances after an acute illness, or from a mental illness as such. In clinical practice, illness-related capacity impairments should in any case be described concretely on a behavior basis [28]. Neurological illnesses are most often associated with (neuro-) mental functioning problems [6], which can be accompanied by impairments in psychological capacities. After a stroke, a patient may be impaired in group discussions, due to speech problems.

Conclusion

Across all three somatic illness groups, a relevant part of patients had at least one capacity which is observably impaired. Neurological patients showed stronger impairments than orthopedic and cardiological patients in all capacity dimensions.

Rehabilitation medicine should consider diagnostics of capacity impairments more routinely. Capacity impairments are a senseful basis for deriving therapy goals on capacity and participation level, which is useful for capacity trainings [41], or context adjustment.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data can be requested from the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was funded by the German Pension Fund under Grant 8011 − 106 − 31/31.129. Funding was acquired by the author B.M.