Advances in public health and medical technology have resulted in continued increases in life expectancy across developed countries . Within the UK alone the projected rise in adults aged over 80 years is due to rise from 2.9 million adults in 2010 to 5.9 million in 2035 . These increases in life expectancy are presenting significant challenges to existing healthcare systems with regards to the management and treatment of patients with chronic or disabling illnesses [1, 3]. This is manifesting itself in an increased reliance on informal carers as a fundamental part of patient management which has become important following an increasing emphasis upon outpatient treatment of patients with chronic physical health conditions . Currently around 5 million people in the UK provide informal care to someone with a physical or mental health difficulty .
The shift to outpatient treatment alongside a concomitant increase in the role of informal carer in patient management and treatment has led to a reduction in patient hospital and physician care as well as delaying the receipt of nursing home care . However given demands associated with supporting the treatment and recovery of patients with a physical or mental health difficulty now being placed upon informal carers, the potential is that costs are simply being shifted elsewhere. Informal care is not only associated with greater risks of poor mental and physical health [7–10] but additional personal and societal costs arising from reductions in hours of paid work, restriction in social and recreational activities , and sleep disturbances . Additionally poor mental health in carers may also negatively impact on outcomes associated with the care recipient .
A clear need therefore exists to develop evidence-based psychological interventions to support the long-term emotional needs of informal carers. However such long-term emotional needs of carers have been neglected across a range of chronic physical health conditions [14–18]. Furthermore, services that do exist to provide emotional support are often inadequately developed and are generally not tailored to address the unique difficulties carers’ experience . Such difficulties may include the management of behavioural problems , physical impairments , cognitive decline  and the development of communication techniques . Developing interventions have however potentially been hindered given that the needs of carers often change dependent upon the course of the chronic physical health condition of the care recipient, the setting care is provided in and length of time care has been provided . Recognition of the unique and multifaceted needs of informal carers has led to the suggestion that multicomponent interventions are required [17, 23].
A number of meta-analyses have been undertaken to identify factors associated with positive outcomes in informal carers, such as caregiver burden, knowledge, depression and symptoms of care recipients. Commonly such meta-analyses have included a large number of potential factors, such as respite and day care, knowledge and training, group- and individual-based interventions, type of setting and various caregiver characteristics . Additionally they have focused upon a variety of specific patient carer groups such as stroke , cancer  and dementia [23, 27]. Far less attention has however been directed towards identifying specific psychological interventions that may be targeted at the treatment of depression and anxiety. Where this focus has been included within the meta-analysis as treatment moderators, psychological treatments mostly consistent with elements of cognitive behavioural therapy (CBT) have been identified to have a small effect on caregiver depression [24, 28]. Furthermore, one review has identified cognitive reframing, a specific component commonly found within CBT, as an intervention component promising for depressed informal carers of dementia patients .
To date little research has sought to identify specific intervention components that have been utilised in interventions targeting depression and anxiety in carers of adults with chronic physical health conditions. Additionally, when such components have been identified through approaches such as systematic reviews, it has been reported that too little attention has then been paid to identifying the specific components associated with effectiveness [29, 30]. Recent systematic reviews have therefore examined not only the overall effectiveness of interventions but also the specific intervention components associated with their effectiveness [30, 31]. This systematic review therefore seeks to examine both the overall effectiveness of psychological interventions for depressed or anxious carers and specific intervention components associated with effectiveness. The identification of effective intervention components utilised in interventions targeting depression and anxiety in carers of adults with chronic physical health conditions is an important next step to inform the future design and development of evidence-based treatments.
First, to undertake a comprehensive systematic review and meta-analysis examining the effectiveness of psychological interventions targeted at treating emotional difficulties, such as depression or anxiety, across a range of carer-care recipient populations. Second, to identify intervention components associated with effectiveness. The results of the systematic review will also be used to feed into the development of an evidence-based complex intervention for carers of people with chronic physical health conditions using the Medical Research Council’s (MRC) guidance [32, 33].