Alzheimer's disease (AD) involves progressive degeneration of the brain, leading to impaired memory, thinking, behaviour, self-care and personality, and, eventually, death. In Hong Kong, approximately 60,000 people live with AD. This costs US$1,129.7 million in 2005, including US$260.6 million spent on home-based informal care. (1) The ecological theory was developed by Urie Bronfenbrenner (2) in the 1970s and has had a significant impact on the investigation of individual behaviour through multiple factors. According to this theory, every single person embeds into 4 layers: (1) the micro-system, the innermost layer; (2) the meso-system, the second layer; (3) the exo-system, the outer layer; (4) the macro-system, the outermost layer. In brief, the microsystem contains the structures with which the individual has direct contact, such as the family and school. The mesosystem refers to the connections between two or more micro-systems such as the family. The exo-system, which is a larger environmental system, exerts an indirect impact on the individual, and includes the social security and medical care systems. Lastly, the macro-system comprises the culture, the customs, and the legal, political, and economic systems, which in turn impact on all other systems. The ecological theory emphasises person-environmental exchanges across the lifespan. Through understanding the connections between caregivers and their different systems, professionals can better utilise the strengths of the systems and thereby choose the best possible interventions across the layers.
In the ecological theory, social support and its influence originate from different systems to exert impact on the individual. Social support has the potential to help us understand the dynamic interactions between the individual and the social environment. (3) Albee (4) argued for the prominent role of social support in his analyses linking prevention to the epidemiology of psychopathology. A negative correlation has been found between social support and depression in older adults and the caregivers of patients with dementia. (5,6) It has been shown that the survival and quality of life of people with dementia is related to the well-being of their caregivers. (7) Caregivers may experience adverse psychological, physical, social, and financial consequences. Many caregivers become socially isolated soon after adopting the caregiver role, leading to lower levels of psychological well-being. (8,9)
The caregiver role is crucial to community care of patients with dementia. Social support may relieve the burden on caregivers and help them adapt better to the caregiving role. (10-12) A recent meta-analysis of the dementia caregiver literature has established 2 major domains with important empirical influences on caregivers' adjustment in terms of burden and depression: firstly, the care demands posed by the care recipients' characteristics, and secondly the resources available to the caregivers. (13) Successful interventions devised by clinicians and researchers reduced caregivers' distress, depression, psychological morbidity and delayed admissions to nursing homes, and improved patients' psychological well-being. Various task-specific and function-specific models suggest that different sources of support serve different functions. Litwak (14) advocated that various sources of support (e.g. friends versus spouse) typically provided different types of support (e.g. companionship versus housecleaning). Crohan and Antonucci (15) found that family members often provided more instrumental support, whereas friends usually provided more emotional support and companionship. Weiss's functional-specificity model found that the individual's requirements for specific forms of support could be met only within certain relationships. (16) When the same type of support was given by different sources, the impact was often not the same. In accordance with this theory, Simons (17) asserted that it was merely the relationships between older participants and their spouses and children that determined feelings of security. …