Social relationships, mental health and wellbeing in physical disability: a systematic review

Disability is a growing public health problem, not least in ageing populations worldwide [1]. People with functional limitations or bodily impairments are generally disadvantaged in their opportunities to participate in social life [2]. These restrictions not only contradict basic human rights [3], but may also affect people’s health and wellbeing. There is consistent evidence that continued favourable exchange with one’s proximate social environment (e.g. family, friends and work life) exerts beneficial effects on health and wellbeing [4]. Conversely, social isolation or lack of close social ties is associated with poor health and increased mortality risk [5]. These associations hold true for the general population but are particularly relevant for persons with physical disabilities, due to their restricted social participation [6]. Reduced mental health in terms of psychiatric disorders is one of the major burdens of disease worldwide [7] and in particular in populations with disabilities [8].

There is convincing evidence that poor social relationships negatively impact mental health [9, 10]. So far, systematic reviews have summarized the links between social relationships and mental health in able-bodied populations [10], yet, no systematic review has been performed to document the current state of research in persons with physical disabilities. Traditionally, mental health is understood as a multidimensional construct of disease orientated symptoms [11, 12]. Given the pervasive effects of disability on major areas of everyday life, it is important to consider the subjective appraisal of one’s wellbeing. More precisely, wellbeing defined as the subjective appraisal of one’s functioning, mood and satisfaction with life complements the concept of mental health to represent this important dimension [13]. This review incorporates this distinction by analyzing the associations of social relationships separately for mental health and wellbeing.

Given the variety of concepts and measures of assessing social relationships, we first define the leading concepts as a prerequisite to structure the bulk of information provided by the extensive body of empirical data. The term social relationships encompasses a wide variety of aspects relating to the proximal and distal social environment. Distal environment includes the broader social structure of opportunities for social integration (e.g. cultural, labour market, neighbourhood) and its quality (e.g. social capital) [9, 14]. Aspects of the distal social environment are excluded from this review as direct effects on health and wellbeing are usually weak or absent after analyzing their mediation through proximal factors [15], and as evidence for populations with disabilities is widely lacking. Our work therefore focuses on two leading sociological concepts that analyse proximal factors of social relationships, namely social networks and social support [14]. Social networks describe the size, density, frequency and duration of social contacts [16], whereas social support emphasizes the functional significance in terms of providing instrumental, emotional or informational resources [17]. Important further aspects concern the quality of and satisfaction with support received and the distinction between perceived and received support. Further aspects look at the dynamics of specific relationships, for example the relationship quality [18] of dyadic couples or family functioning [19, 20]. Not all social interactions result in positive relationships and negative social interactions will also form a part of this review [21]. Finally the notion of loneliness is relevant in this context because the subjective feeling that it represents may have adverse effects on mental health and wellbeing, even in the presence of social contacts [22, 23]. We explore these aspects of social relationships from the perspective of persons with physical disabilities in order to assess how their perception of their interaction with the social environment is associated with mental health and wellbeing. Aspects of informal caregiving are not explicitly included in this review but may arise due to the inclusion of family functioning and received social support.

The objective of this review is thus to summarise a complex and heterogeneous body of empirical research on the association of different social relationship constructs with mental health and wellbeing in physical disability and to highlight conceptual and methodological deficiencies in the field of research.

Table 1 shows an overview of the social relationship, mental health and wellbeing constructs under study along with the participant characteristics of the included studies. The vast majority of the 63 included studies focussed on social support (n = 58), with relatively few other constructs being identified: Social networks were assessed in six studies, negative social interaction in three studies, family functioning in two studies, and relationship quality in one study. Concerning mental health and wellbeing constructs, depression was the most heavily studied construct being reported by 33 studies, a composite mental health score was reported by ten studies, followed by anxiety (n = 8), psychological distress (n = 7), posttraumatic stress disorder (n = 3), and hopelessness (n = 1). The health condition most prolifically studied was rheumatoid arthritis, particularly due to the inclusion of several studies from a large scale European-wide study focusing on social support in arthritis (EURIDISS) [28]. The mean STROBE sum score was 13.5, ranging from 8 to 19. The description of any efforts to address potential sources of bias (met by 9.5% of included studies) and the explanation of how the study size was arrived at (met by 7.9% of included studies) were the two STROBE criteria which were most frequently unmet.

Tables 2 and 3 provide a summary on characteristics and key findings of included cross-sectional and longitudinal findings, respectively. Results are presented along the social relationship constructs I) social support, II) social networks, III) negative social interactions, IV) family functioning and V) relationship quality. For all five constructs, we first present an overview on study characteristics (specification of constructs, measurements, study quality), followed by an in-depth discussion on cross-sectional and longitudinal findings.

Of the 58 studies focussing on social support, 45 were cross-sectional and 13 longitudinal. Social support constructs were operationalized heterogeneously, including type (emotional, instrumental, affective or tangible) or source (e.g., family, friends, significant other) of social support, overall measures of perceived or received social support, satisfaction with support, negative social support or unavailability of support. Four studies assessed received social support, defined as actual exchange of support [29‐32]. Six studies report their results according to type of social support [31‐36]. Two studies looked at negative or problematic social support [37, 38], two at the unavailability of social support [37, 39], and three studies distinguished between the source of social support (friend, family, significant other) [40‐42]. The remaining 44 studies investigated perceived social support or satisfaction with support, although precise definitions of the terms under study were often missing. This heterogeneity of used constructs is reflected by the fact that we found a total of 21 different measures to assess social support. Overall, we did not observe any systematic association between study quality and strength of associations for studies including a social support measure.

Cross-sectional findings. 33 of the 45 cross-sectional studies found a significant association between social support and mental health and/or wellbeing, while three studies reported a non-significant trend [43‐45], two studies showed no association [46, 47] and seven did not test the association in multivariable analyses [30, 48‐53].

More specifically, of the 25 studies assessing depression, 14 found an inverse association between some element of social support and depression [29, 33, 34, 37‐39, 42, 54‐60], six studies reported a trend towards an inverse association [43, 45, 61‐64], and one observed no association [46]. Two studies tested associations only in bivariable analyses and found no significant correlations [30, 53]. As mainly composite scores of social support were used, it was not possible to identify whether a certain aspect of social support was more protective than another. Of the four studies assessing anxiety, none reported a consistent association [53, 61, 64, 65]. A total of three studies looked at posttraumatic stress disorder (PTSD). While two of them only performed bivariable analysis [48, 66] one found a negative association between social support provided by friends and PTSD [40]. Of the nine studies assessing composite scores of mental health, seven found a positive association [41, 67‐72]. Of the 14 studies assessing wellbeing, eight reported a positive association in multivariable analysis [33, 58, 63, 64, 73‐76] and three studies did not report the results for multivariable analysis as bivariable associations were insignificant [49‐51].

Longitudinal findings. Of the included longitudinal studies, 15 out of 16 involved a social support construct (Table 3). Results suggest that at very early stages of the disease process social support increased over time [35, 77] only to decrease at later stages [31, 78]. Four studies looked at social support’s association with psychological distress [35, 78‐80]. Three of these studies found a change in psychological distress over time as a function of social support [78, 80, 81], whereas one study only found cross-sectional associations [79]. The one study only which distinguished between emotional and instrumental support observed associations of distress with emotional support but not with instrumental [35]. Seven studies analysed the association between social support and depression, two of these studies showed evidence of a longitudinal relationship between social support and depression [82, 83], i.e. earlier measures of social support effecting depression at later time points. Three studies only found cross-sectional associations [36, 77, 84] and two studies could not observe any association between social support and depression [85, 86]. The three studies addressing anxiety as an outcome showed no longitudinal associations with social support [84‐86].

Four cross-sectional studies included a measure of social networks as an independent variable (Table 2) [65, 76, 87, 88]. All measures of social networks addressed the size of network in terms of the frequency of interaction with different members or organisations of the network. Associations to depression were limited to men in one study [65] or to both men and women in a study of low quality [87]. There were no significant associations of social networks with a composite measure of mental health [88], anxiety [65], or wellbeing [76].

Of the included longitudinal studies, two out of 16 included social networks as an independent variable (Table 3) [84, 86]. Both studies assessed the same population at different time points and were of low quality. In both studies, social networks showed weaker associations with depression and anxiety than perceived social support. One study found a negative association between social network in terms of number of friends shortly after diagnosis and depression 1 year later [84].

Three cross-sectional studies looked at negative social interaction (Table 2) [45, 65, 68]. Aspects of negative social interaction included lack of understanding, criticism and negative spousal responses to pain. All of these studies were medium in quality, two of which solely focused on interactions within partnerships [45, 65], whereas one also investigated negative responses from different sources such as family members and colleagues [68]. All three studies provide evidence for associations with mental health: Negative associations between discounting, lack of understanding and mental health were found to be statistically significant [68], along with positive associations of criticism with anxiety [65], and of negative partner responses to pain with depression [45].

Two studies looked at family functioning [37, 89], one of high quality [88] and one of low quality [37]. Inverse associations of family functioning with depression [37, 89] and negative affect [37], and positive associations with life satisfaction were found [37], but none with hopelessness [88]. Effect sizes of associations of family functioning with negative affect and depression were similar to those of social support, but somewhat larger for associations with life satisfaction [37].

The one cross-sectional study which assessed relationship quality found an inverse relationship between relationship quality and depression [90]. This cross-sectional finding was supported in an additional longitudinal study, although there was no evidence of a longitudinal association [91]. Both studies were rated medium in quality.

In this review, we summarised a complex and heterogeneous body of empirical research on associations of social relationships with mental health and wellbeing in physical disability. When basing conclusions solely on results reported from multivariable analyses, we found consistent associations between social support and composite scores of mental health. The associations of social support with anxiety, depression and wellbeing were less pronounced as many studies reported insignificant associations. Remarkably, social networks seem to be related to depression, but not to any of the other studied measures on mental health or wellbeing. In contrast, family functioning, negative social interactions and relationship quality showed consistent associations with indicators of mental health and wellbeing, although the evidence was limited due to the small number of studies focusing on these concepts.

The aspect of social support is particularly dominant in disability research. Social support is considered a vital resource for hindering the negative consequences of a wide variety of stressors in disability (the ‘buffering hypothesis’ of social support [92]), including the chronic stress of physical disability itself. However, the number of studies which found insignificant or weak associations of social support with depression indicates limited support for this hypothesis. A review looking at social relationships and depression in the general population found 91.4% of studies to report a significant inverse association between social support and depression [93], in comparison we found only 59.0% of studies to report such an association. Moreover, the composite scores of social support which were often used in analysis integrated many distinct aspects of social support, often including items assessing received support alongside those assessing perceived support thus making it difficult to disentangle how different aspects of social support affected mental health and wellbeing. Inconsistent associations between social support and depression may therefore be explained by the potentially adverse effects of receiving social support in disability. Unwanted or unnecessary receipt of instrumental social support may have negative consequences among persons with disabilities, leading to reduced autonomy, self-worth and personal responsibility, all factors which are related to mental health and wellbeing [94]. Furthermore, when learning to interact with people in times of stress, such as during the adjustment and adaption to disability, high levels of social support could lead to higher levels of psychological distress. Moreover, increased support may be recognised or mobilised during times of distress, thus increasing the complexity of the relationships and the potential for reverse causality [95]. Evidence for the association of received instrumental support with mental health and wellbeing was lacking in this review, perhaps owing to the fact that long-term received support is often termed as ‘informal care’ in the literature.

The observation of inconclusive associations of social networks with indicators of mental health and wellbeing might be explained by the fact that social networks exert an indirect rather than direct effect on mental health and wellbeing [14]. This explanation is consistent with the conceptual model devised by Berkman et al. which suggests that social support is a resource attainable through access to the upstream factor of social networks [14]. This would suggest that social networks are important in their provision of social support but that their direct effect on mental health is minor. These results support the hypothesis by Cohen and Wills that qualitative support is more significant than social integration for persons under stress, i.e. persons with disabilities [92]. Additionally, extensive networks may not necessarily be supportive and members of social networks may be a source of stress or conflict [96].

We conclude that social relationships play an important role in mental health and wellbeing in persons with disabilities, although findings are less consistent than in the general population, strength of associations vary between constructs, and some important constructs such as loneliness, relationship quality or reciprocity are neglected in disability research. Integrating persons with disabilities into social networks is an important endeavour, however, it is of equal importance to strengthen the quality of their relationships and to tailor the level and kind of support to their needs. To promote mental health and wellbeing, rehabilitation professionals should support persons with disabilities and their significant others to ensure that high quality relationships are established and maintained, and that adequate support is available.