1 Introduction

Caregivers are the main source of care for persons with disabilities in any society, especially children. Family or informal caregivers support about 90% of individuals with significant mental health challenges on a daily basis both practically and emotionally [15]. Children with developmental disabilities refer to children that struggle to achieve their daily needs and need support with their everyday activities [7]. Developmental disabilities encompass a variety of childhood conditions and are often used in different ways in various contexts and cultural contexts [42]. Smythe et al. [35] defined developmental disability as a broad category of conditions that can have a variety of implications on how children develop in terms of their sensory, cognitive, and physical abilities. Estimate of about 53 million children less than 5 years of age living with developmental disabilities (attention deficit hyperactivity disorder, autism spectrum disorder, epilepsy, down syndrome, vision and hearing loss, and intellectual disability) suggests that developmental disabilities are remarkably the most common cause of disability in childhood [28]. The children of the caregivers in the current study are children living with developmental disabilities such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), intellectual disabilities, down syndrome, and cerebral palsy. Chukwuemeka and Obioha [7] noted that problems arising from the care of people with disabilities has been reported to have significant effect on both the care recipients and the caregivers themselves. These problems could be a variety of negative outcomes and may range from psychological distress, decreased mental health and well-being and difficulty with emotion regulation [7, 40], stress [18], trauma [32, 41], depression, insufficient sleep quality, decreased life quality [13], as well as higher financial inconveniences [5], which constitutes a significant level of burden that often becomes unbearable for the caregivers. Tomiyama et al. [38] noted that taking care of a child with a disability needs more time, attention, and self-education than raising a child without disability. It is much more difficult to take care of children with developmental disabilities as their continuous need for assistance for their daily functioning places significant burden on the caregivers, which according to Chukwuemeka and Obioha [7], may result in decreased mental and physical health for the caregivers.

Sartorius [33] developed a three-way definition of mental health. First, health refers to the absence of both physical diseases and psychological disorders. Second, health refers to state in which an individual is able to function well in all areas of their lives. Finally, health refers to a balance between the individual and their physical and social environment. Based on the proposition of Sartorius [33], we define mental health in relation to caregiving, as the condition in which caregivers maintain maximum positive functioning even in the face of challenges posed by the act of caregiving. Research has indicated that providing care for family members and individuals with mental health issues can result in a number of negative outcomes, including low self-esteem, persistent worry, feelings of helplessness, financial hardships, social isolation, and occupational constraints [22], which may be risk factors of mental health. Moreover, family caregivers run a higher risk of having a shorter life expectancy, being less happy and proficient in life skills, and spending less time engaging in leisure activities [2, 11, 19, 26].

1.1 Burden of care and mental health

Burden of care refers to the stress resulting from caregiving and is described as the caregiver’s perception and evaluation of the level of stress associated with the process of caregiving. Conceptualisations of burden of care have often varied depending on the context and on the type of disability [36], but a common consensus is that it constitutes a significant level of distress or inconvenience for the caregivers. More than 80% of caregivers report feeling burdened by their work, a phenomenon that is widely documented worldwide [36]. Burden of care have been found to impact mental health of caregivers in mostly negative ways [6]. Caregivers who perceive higher caregiving problems find it difficult to navigate the stress associated with caregiving and are more prone to reduced mental health unlike caregivers who perceive little or no burden of care. This is so because caregivers put even more effort than is required into the care of children with developmental disabilities, as they invest their financial, social, mental, and physical resources to fulfil their caregiving obligations [19].

Ahmad et al. [1] noted that many patients with mental disabilities or psychiatric problems are now increasingly being taken care of at home by informal caregivers. However, it’s possible that a large number of informal caregivers who take on duties lack the necessary knowledge and expertise to provide care. Many caregivers have also reported experiencing significant psychological distress and heavy burdens due to their lack of readiness for the role of informal caregiver [2]. Thus, mental health issues would affect not just the individual with the ailment but also others who provide care for them [4]. Research indicates that, in contrast to the general population, caregivers of patients with mental health concerns experience higher rates of mental health difficulties. Even while the advantages and disadvantages of giving care aren't always clear, they frequently lead to high levels of stress among caregivers [21]. Numerous reviews (e.g., [3]) have examined caregiver burden across a range of caring categories, including caregivers who live with persons with dementia. Because dementia caregivers are socially isolated due to the nature of their caring tasks, these reviews discovered that burden and burnout syndrome were linked to caregivers' quality of life. The results also demonstrated the high need for interventions in this population that effectively reduce symptoms and burden associated with caregiving [8]. Caregivers' health, relationships, social life, and employment are all significantly impacted by the need and obligation to provide care, which can leave them feeling unhappy and dissatisfied. For enhanced mental and psychological functioning, caregivers must find an antidote to these mental health issues related to providing care; hence, resilience may be a potentially favourable factor that may enhance adaptation and coping with caregiving and serve as potential cushion for the caregivers.

1.2 Resilience and mental health

Connor and Davidson [9] defined resilience as a psychological quality that permits appropriate coping with adversity. According to Obioha et al. [27], resilience is the ability to remain resolute and function well irrespective of one’s encounter with stressful situations and adversities. Using the pathway to resilience, developed by Theron et al. [37], two conditions must be fulfilled before resilience is achieved. First, there must be a situation of adversity. Second, individuals must successfully cope with this situation. Therefore, resilience is said to have occurred when an individual successfully adapts to an identified situation of adversity. In the context of caregiving, the adversity situation could be the burden of care which is posed by the care of children with developmental disabilities. In line with the pathway to resilience, caregivers are resilient only when they are able to successfully cope with the burden posed by caregiving. Therefore, caregivers who are able to manage the burden of care may more plausibly be associated with enhanced mental health, since resilience has often been used to explain coping mechanism that promote mental health outcomes.

Davydov et al. [12] suggested that a resilient individual can maintain their psychological well-being even under challenging circumstances and unfavourable settings. Resilience is linked to a quick and efficient recovery from stress and is regarded as an “immunological barrier” that permits a certain level of wellness. Hence, many researchers link the idea of resilience to improving psychological well-being [29]. Additionally, other researchers emphasized how critical it is to comprehend resilience while creating treatments to cure or prevention of mental illnesses, especially stress, anxiety, and depression [31]. Resilience is linked to the development of abilities including self-esteem, internal cohesion, regulating emotions related to trauma, managing symptoms, integrating memory and emotion, controlling memories of a traumatic event, creating safety signals, comprehending the effects of trauma, and arriving at a positive meaning, all of which are considered important for mental health [17]. Similarly, resilience enhances mental and physical health, increases survival, and greatly decreases the chance of developing chronic stress, anxiety, depression, and other health problems [10].

1.3 Theoretical background

The Stress and Coping Theory [23] provides useful insights into how caregiving may contribute to stress or significant burdens for the caregivers as well as how caregivers may cope with the stressors associated with caregiving. The theory provides a helpful framework for developing and evaluating theories regarding the stress-related mechanism and its connection to mental as well as physical wellness. The stress and coping theory applies to the way that stress is felt throughout regular life events, significant life events, and long-term, chronic stressful situations. This explains its relevance to caregiving since caregivers may often perceive stress associated with caregiving. According to Folkman [14], stress is defined as an individual's connection with their surroundings that is deemed personally significant, demanding, or requiring more resources for coping than they have. Stress may occasionally arise from the environment, hence, the theory emphasizes the importance of appraisal and coping, noting that appraisal and coping may be essential mediators of the relationship between the individual and their environment (i.e., stress). Resilience is quite pronounced within these two processes since resilience can be seen as a type of adaptive coping that aids in the management of caregiver stress brought on by caregiving responsibilities. The term “appraisal” describes a person’s continuous assessment of how circumstances are progressing concerning their objectives, values, and beliefs. Appraisal may explain why certain caregivers may perceive more burden than others. This is because individuals who are able to regulate their emotions using positive emotion regulation strategies such as cognitive reappraisal may experience better psychological outcomes than those who think of their situations in rather negative ways [7]. Reappraising the stressful situation may therefore provide caregivers with actionable coping mechanisms that may contribute to their resilience towards caregiving stress, and further improve their psychological well-being.

1.4 The current study

The current study seeks to investigate the moderating role of resilience in the relationship between burden of care and mental health among a Nigerian sample of informal caregivers of children with developmental disabilities. Although some studies have previously examined the resilience pathways that enable caregivers cope with the enormous demands of caregiving, studies of this type are notably lacking in the African context, which may be attributable to the informal model of caregiving widely used in Nigeria and Africa at large. It is reported that when a caregiver is mentally distressed and burdened, it not only negatively impacts their own productivity and well-being but also the quality of life and health of the mentally ill relative they are caring for. This worsens the care recipient’s condition and reduces the possibility of recovery or improvements in health [39]. Previous studies have also focused on caregivers who care for people with other physical conditions such as cancer patients, while others focused on caregivers of dementia patients and old people, however, only a few have focused on caregivers of children with developmental disabilities. It is therefore pertinent that researchers in Africa give the required attention to the welfare of informal caregivers of children with developmental disabilities and help in the development of effective interventions to enhance their well-being. As a moderator, resilience may play an important role by decreasing the likely negative impact of burden of care on mental health of caregivers or exerting other significant influence that are worthy of being noted in the literature. Obioha et al. [27] noted that resilience is generally thought of as a protective factor in many instances, as it often exerts positive impacts on adversity situations. Therefore, we hypothesize that: (1) burden of care will be negatively associated with mental health of caregivers of children with developmental disabilities, (2) resilience will be positively associated with mental health of caregivers of children with developmental disabilities, (3) resilience will moderate the association between burden of care and mental health of caregivers such that caregivers who have high resilience will maintain high mental health regardless of their caregiving burdens.

2 Methods

2.1 Participants

Participants for the present study were two hundred and twenty-eight (228) parents and guidance of mentally challenges children drawn from the Therapeutic Day Care Center (TDCC), Abapkpa, Enugu. The participants were selected using convenience sampling technique. Of the total sample, 63 were males and 165 were females. The average age of the respondents was 27.85 (SD = 10.06) ranging from 16 to 67 years old. All participants in the study were married and had children with developmental disabilities. With respect to religion, all participants were Christians and from the Igbo tribe. In terms of highest educational qualification, 163 participants had Senior Secondary School Certificate (SSCE), 57 had bachelor’s degrees, while 8 had First School Leaving Certificate (FSLC).

2.2 Instruments

2.2.1 Connor–Davidson resilience scale (CD-RISC)

The Connor–Davidson Resilience Scale [9] is a 25-item self-report scale that measures the ability to cope with adversity. Respondents’ rate items on a scale from 0 (not true at all) to 4 (true nearly all the time). Examples of items include: “I usually manage one way or another”, “I feel proud that I have accomplished things in life”, “I usually take things in stride”, “I am friends with myself”, etc. A preliminary study of the psychometric properties of the CD-RISC in general population and patient samples supported its internal consistency, test–retest reliability, and convergent and divergent validity. Cronbach’s alpha for the full scale was 0.89 and item-total correlations ranged from 0.30 to 0.70 [9]. The current study obtained a reliability coefficient (Cronbach’s alpha) of 0.80.

2.2.2 The Zarit burden interview (ZBI)

The Zarit Burden Interview [43] is a validated self-report instrument consisting of 22 items that assesses the extent to which caregivers perceive burden from caregiving. The tool assesses the psychological state, emotional stability, social and familial relationships, financial situation, and level of personal control of caregivers. Every question has a 5-point Likert scale, with 0 representing never and 4 representing almost usually. The range of total scores is 0 (low burden) to 88 (great burden). Examples of items include: “Do you feel that your relative asks for more help he or she needs?”, “Do you feel that because of the time you spend with your relative that you don't have enough time for yourself?”, “Do you feel stressed between caring for you relative?” etc. The ZBI is reported to have excellent internal consistency (α = 0.83) according to Zarit et al. [43]. The current study obtained a reliability coefficient (Cronbach’s alpha) of 0.88.

2.2.3 The 12-item general health questionnaire (GHQ)

The General Health Questionnaire [16] consists of 12 self-report items, each one assessing the severity of a mental problem over the past few weeks using a 4-point Likert-type scale (from 0 to 3). The GHQ was developed by Goldberg and Williams [16] and is a validated tool used to access the prevalence of psychological distress. It consists of 12 items, six that are negatively worded and assesses presence of psychological distress, and another six that are positively worded and assesses positive psychological state. The items are responded to and scored on a 4-point scale ranging from 0 (never) to 3 (always) with which a minimum score of 0 and maximum score of 36 can be obtained. Usually, when using the 0, 1, 2, 3 scoring pattern, the positively worded items are reverse scored to make them consistent with the negatively worded items; thus, making it a comprehensive measure of psychological distress. In this case, higher GHQ scores indicate higher psychological distress and lower mental health. However, in the current study, the negatively worded items were reverse scored to make them consistent with the positively worded items; thus, making it a measure for positive psychological state or mental health. In this case, higher GHQ scores represent higher mental health while lower scores represent psychological distress. This is supported by Hu [20] hypothesis that the GHQ can measure positive mental health in population-based research. Examples of items includes, “Have you recently been able to concentrate on what you are doing?”, “Have you recently lost much sleep over worry?”, “Have you recently felt that you are playing useful part in things?” The inter-item correlation of the instrument was 0.57 on average. There was a good contribution to the overall score as indicated by the items-total correlations, which varied from 0.62 to 0.86. Using Cronbach's α coefficient, the instrument's internal reliability was determined, and the results showed a value of 0.94 [24]. The current study obtained a reliability coefficient (Cronbach’s alpha) of 0.76.

2.3 Procedure

The researchers went to the Therapeutic Day Care Centre (TDCC) with a letter of identification from the researchers’ institution, to seek for their approval to collect data from caregivers of children with developmental disabilities in their custody. TDCC situated in Abakpa, Nike, Enugu State, Nigeria is a special education institution for special needs children. They provide education and care for children with disabilities. Upon approval at TDCC, the researchers began to administer data to the caregivers, and this lasted over the course of one weeks. Participants were approached by the researchers in their centre and during the parent-teachers association (PTA) meeting to seek for their consent and voluntary participation in the study. The researchers explained the nature of the study to the participants, and what they were required to do. Participants were informed that they are free to withdraw at any stage of the study, without any prejudice, and that their personal information would remain confidential. Participants who gave their consent and volunteered to participate in the study were then given the questionnaires to fill, while the researchers stayed around to answer any questions that may arise or give assistance when the participants are in need of assistance. A very few but undocumented number of caregivers declined to participate in the study due to time constraints. At the end of data collection, there were 258 returned questionnaires out 270 administered. Out of the 258 returned questionnaires, 12 were returned empty, while 18 were incorrectly responded to and therefore considered invalid. There were 228 valid responses which were used for further analyses.

2.4 Data analyses

This study is primarily survey research and adopted a cross-sectional correlational design. The Pearson correlation (r) was used to examine the zero-order correlation among the study variables, while model 1 of the Hayes PROCESS module (4.2) was used to test the study’s hypotheses. The IBM Statistical Package for Social Sciences (SPSS version 27) was used for the data analysis.

3 Results

Table 1 shows the means, standard deviations, and correlations among the study variables. Older age was positively associated with higher level of education (r = 0.39, p < 0.001). Females were associated with higher level of burden of care (r = 0.13, p < 0.05). Higher educational qualification was associated with lower resilience (r = − 0.15, p < 0.01) and lower mental health (r = − 0.25, p < 0.001), but associated with higher burden of care (r = 0.14, p < 0.05). Burden of care was negatively related with resilience (r = − 0.16, p < 0.05) and mental health of caregivers of children with developmental disabilities, (r = − 0.48, p < 0.001). Resilience was positively related with high level of mental health of informal caregivers of children with developmental disabilities (r = 0.27, p < 0.001).

Table 1 Mean, standard deviation and correlations of demographic factors, burden of care, resilience, and mental health of informal caregivers of children with developmental disabilities
Full size table

Results in Table 2 showed that burden of care was negatively associated with mental health of informal caregivers of children with developmental disabilities (B = − 0.21, p < 0.001). The B showed that each unit rise in burden of care was associated with a 0.21 decrease in mental health of informal caregivers of children with developmental disabilities. Resilience was positively associated with mental health of informal caregivers of children with developmental disabilities (B = 0.09, p < 0.01). The B showed that each unit rise in resilience was associated with 0.09 increase in mental health of informal caregivers of children with developmental disabilities. The interaction of burden of care and resilience was not significant (B = − 0.00), indicating that resilience did not moderate the relationship between burden of care and mental health of informal caregivers of children with developmental disabilities. Although not a major variable in the study, as a controlled variable, education was negatively associated with mental health among informal caregivers (B = − 2.51, p < 0.01), indicating that increase in education was associated with decreased mental health among caregivers. The R2 of 0.29 for the model indicated that 29% of the variance in mental health of caregivers of children with developmental disabilities was explained on account of the entire variables, F (4, 222) = 26.97.

Table 2 The Hayes PROCESS Macro results for predicting mental health of informal caregivers of children with developmental disabilities by burden of care and resilience with education as a covariate
Full size table

4 Discussion

This study investigated the roles of resilience and burden of care on mental health of informal caregivers of children with developmental disabilities, as well as the moderating role of resilience in the relationship between burden of care and mental health of these informal caregivers. In line with our first hypothesis, the result revealed that burden of care was a significant negative predictor of mental health of informal caregivers of children with developmental disabilities, indicating that increase in burden of care was associated with low mental health outcomes for caregivers of children with developmental disabilities. This is consistent with previous studies (e.g., [34, 39]) which found that burden of care has negative impacts on mental health outcomes, depicting that when informal caregivers of children with developmental disabilities experience greater burden of care, they stand at risk of developing mental health problems including depression, psychological distress, difficulty in emotion regulation, etc. The study also tested resilience of the informal caregivers of the children with developmental disabilities and found that resilience was a significant positive predictor of their mental health, indicating that increase in resilience was associated with high mental health among informal caregivers of children with developmental disabilities. This is consistent with the findings of previous studies (e.g., [10]) which suggested that high resilience is associated with positive impacts on mental health. Resilience should therefore be considered as a protective factor that has the potential to enhance the mental health of caregivers of children with developmental disabilities.

Further, we found that resilience did not moderate the relationship between burden of care and mental health of caregivers of children with developmental disabilities. This finding did not support our hypothesis as we expected that resilience could be able to reduce the risky impact of burden of care on caregivers’ mental health. Rather, the results provided evidence that the relationship between burden of care and caregivers’ mental health is linear and is not affected by their level of resilience. This may imply that whether or not caregivers resile does not affect their mental health status when they perceive greater burden of care. By implication, this finding suggests that burden of care is a potentially strong risk factor for the mental health of caregivers and requires interventions that are not only within the caregivers themselves (e.g., resilience), but also those that are external to the caregivers (e.g., social support). For example, Ong et al. [30] found that resilience decreases the burden perceived by caregivers when there is sufficient social support. Although on the direct path, resilience was found to be a protective factor for caregivers’ mental health, but the moderation finding suggests that resilience may not play this protective role if the caregivers perceive overwhelming burden resulting from the care of children with developmental disabilities. It may also suggest that the caregivers do not have adequate level of resilience that is necessary to adapt to the caregiving burden or that they do not have enough resources available to help build their resilience. Therefore, as suggested by Obioha et al. [27], some important resources need to be made available as they help individuals to develop adequate level of resilience. This may include a functional and supportive family network, favourable policies, social support, etc.

4.1 Research implications

The current study has important practice-based implications. Nigeria among most other African countries is widely known to adopt the informal model of caregiving in which the elderly, the sick, and those with any forms of disabilities are taken care of at home by their close relatives. Consequently, care is being given by those who lack the professional expertise to administer care and have therefore been largely underrepresented in the caregiving literature. Informal caregivers receive little attention than formal caregivers as it is widely noted that formal caregivers receive more resource allocations [25]. However, informal caregivers do not receive resource allocations and do not often expect such because they see the care they provide as their duties for their loved ones. The fact that their welfare is not usually a matter of concern may result in higher perceptions of burden that may further diminish their mental health. Therefore, resources need to be mobilized for informal caregivers to ensure their maximum functioning. Interventions programs are suggested, in which caregivers are oriented on how to better maximise the resources available to them to build resilience and successfully adapt and navigate the burden associated with caregiving. Family and friends of caregivers are encouraged to be highly supportive and available to assist caregivers whenever necessary. This availability of support may contribute to increased resilience that may then be able to reduce the negative impact of burden of care on the mental health of caregivers. Positive help seeking behaviours should also be encouraged among the caregivers. They should be properly oriented on how to seek help from professionals such as social workers and psychologists when they feel that the burden of caregiving is beginning to get into their nerves. Finally, this study also presents some empirical implications. It will help to update the current state of knowledge on caregivers’ welfare in Nigeria. Many studies on caregiving were conducted in settings outside the Nigerian context and may not permit generalisation to a local Nigerian context.

4.2 Limitations of the study and suggestions for further studies

Despite the relevance of this study, it is important to note some of its limitations. The study may not be generalized as participants were gathered from only one locality; hence, replication studies in varying localities are highly encouraged. The cross-sectional nature of the study is another remarkable limitation of this study. As Obioha et al. [27] noted, cross-sectional studies have received criticisms due to their insufficient power to support inferences and causations, suggesting that longitudinal, prospective, and mixed method designs be adopted in order to eliminate notable method biases and permit wider generalization. The inability to access more caregivers resulted in a small sample size that also limits the generalization of this study. Additionally, the sample was not normally distributed across various categories. For example, all participants in the study were, married, Christians and Igbos, giving no room for comparisons to any other category. Future studies are encouraged to recruit more caregivers that are representative of the caregiver population.

5 Conclusion

This study investigated the direct impacts of burden of care and resilience on the mental health of informal caregivers of children with developmental disabilities, as well as the moderating role of resilience in this relationship. The study presents some important findings; (1) resilience positively predicted informal caregivers’ mental health, implicating resilience as a potential protective factor that may enhance their mental health, (2) burden of care negatively predicted mental health of informal caregivers, implicating burden of care as a potentially strong risk factor informal caregivers’ mental health, (3) resilience did not moderate the relationship between burden of care and mental health of informal caregivers, suggesting that the burden experienced by caregivers may be overwhelming in such a way that their level of resilience is not able to help them adapt successfully to the burden. The study concludes that resources (e.g., social support, favourable policies, intervention programs, etc.) need to be made available for informal caregivers to help them build adequate level of resilience that may result in better mental health outcomes regardless of the caregiving burden they perceive.