Anxiety and depression symptoms among caregivers of care-recipients with subjective cognitive decline and cognitive impairment

Caregiver burden is common in dementia. This condition is not only associated with adverse emotional states and psychiatric morbidity but also poorer physical condition and worse financial and social consequences. Factors in three other domains are also relevant: care-recipient characteristics, caregiver characteristics and living conditions [1‐3]. Previous studies have reported that approximately 22 % of caregivers experience clinical depression [4], and approximately 75 % of caregivers experience significant depression and anxiety symptoms [5, 6]. Mild cognitive deficits are not sufficient for a diagnosis of dementia; however, care-recipients with mild cognitive impairment (MCI) have a 10–12 % annual probability of progression to dementia [7‐11]. One study also indicated that caregivers of care-recipients with MCI showed anxiety and depression symptoms [12].

Subjective cognitive decline (SCD) in older adults is increasingly recognized as a potential indicator of non-normative cognitive decline, and some people with this condition eventually progress to dementia [13‐17]. The core of the definition of SCD is self-experienced concerns about persistent decline in one or more aspects of cognitive function that are typically informant-corroborated; however, they show no impairment in activities of daily living and typically scores within normal limits on standard neuropsychological tests [18‐20]. A previous study showed that the annual conversion rate (ACR) of SCD to dementia is 2.33 % (95 % CI: 1.93–2.78 %), and that of SCD to MCI is 6.67 % (95 % CI: 4.70–8.95 %) [17].

Regarding the persistent cognitive decline and the high rate of its conversion, we assumed that both care-recipients and their caregivers would suffer from cognitive complaints. However, psychiatric symptoms among SCD-caregivers have been under-researched. This study explored the prevalence of and risk factors for anxiety and depression symptoms among caregivers of care-recipients with SCD and cognitive impairment using data from the Memory Clinic of Huashan Hospital in Shanghai.

The demographic, medical history, neurology tests, psychiatric assessment and neuropsychological assessment data of the 343 pairs of care-recipients and caregivers are shown below.

In our study, 26.5 % of caregivers had anxiety symptoms, and 22.4 % had depression symptoms. For caregivers of care-recipients with dementia, MCI or SCD, the rates of anxiety symptoms in were 28.8, 30.0 or 17.9 %, respectively; whereas the rates of depression symptoms were 20.9, 24.2 or 22.6 %, respectively. The risk factors for caregiver’s anxiety symptoms were higher CMAI scores, higher GDS scores, increased caregiver age and having a male care-recipient. The risk factors for caregiver’s depression symptoms were lower TEQ scores, higher GDS scores, increased caregiver age and caring for care-recipients with SCD or MCI.

The prevalence of depression symptoms among caregivers of care-recipients with SCD or MCI was higher than that among caregivers of care-recipients with dementia. The prevalence of anxiety and depression symptoms among caregivers of care-recipients with dementia was in accordance with that in previous studies [4, 6, 52]. The pooled depression rate of caregivers of care-recipients with MCI (CESD scores ≥ 16 or equivalent, total N = 929) was 23 % (11–24.6 % for individual studies) [12], which is in accordance with our results. One study suggested that dementia plays a significant role in caregiver’s depression among Latino families compared with cognitive impairment but not dementia (CIND) [53]. However, most studies have found that depression and anxiety symptoms among caregivers of care-recipients with dementia are not associated with level of cognitive impairment [54‐56]. Another study showed that cognitive function and dementia severity were not correlated with caregiver burden [57]. One possible explanation for our findings is that care-recipients with SCD might often complain about their own declining memory and refer to the effect of their declining memory on activities of daily living. These complaints draw the attention of caregivers and require support and care. When caregivers hear the complaint about declining memory from care-recipients who didn’t previously complain, and are unable to access the support that care-recipients need, caregivers might feel depressed. Another possible explanation is that prior to diagnosis, psychiatric symptoms are more stressful to caregivers because their etiology is unclear, leading to higher caregiver’s depression. After diagnosis, psychiatric symptoms are likely attributed to the process of MCI. With the care-recipient’ further cognitive decline, however, the caregivers become familiar with the disease, able to care for the care-recipients and able to accept the current situation. A third reason might be that care-recipients with mild or moderate dementia, not the severe dementia observed in our study, have relatively mild mental symptoms and do not become a heavy burden on their caregivers.

We found that care-recipient GDS scores were a risk factor for both anxiety and depression symptoms among caregivers; however, we did not find that care-recipient ZSAS or AES scores were associated with caregiver’s anxiety or depression symptoms. Most studies have found that depression and anxiety symptoms in caregivers of people with dementia are strongly associated with patients’ psychiatric symptoms, particularly, depression symptoms [55, 58‐62]. Furthermore, we found that older caregivers had higher risks of both anxiety and depression symptoms. In an Italian multicenter study of 419 elderly outpatients with dementia and their caregivers, increased caregiver age was a major risk factor for both depression and anxiety (BDDA) among caregivers [63]. However, another study of caregivers of people with cognitive impairment did not find that age was an important predictor of caregiver’s anxiety [6, 64]. This finding might be because the physical functions of older caregivers are worse; thus, they become anxious and depressed given the increased burden.

Our study showed that care-recipient CMAI scores were only related to caregiver’s anxiety symptoms. A study of 35 patient-caregiver pairs evaluated at two university-affiliated dementia clinics found highly significant correlations between patient agitation and caregiver burden (r = 0.59, p = 0.0002) as well as between depression and caregiver’s depression (r = 61, p = 0.0001) [65]. A Chinese study found a positively correlation between the agitation among patients with dementia in nursing homes and the stress of 40 nursing staff members [66]. The reason for this finding might be that in addition to the constant daily care they provide, nursing staff must also spend more energy and time preventing care-recipient' self-harm and harm to others. If these effects cannot be predicted or prevented, then it might lead to serious consequences, and make caregivers feel persistently anxious. Furthermore, our study also showed that caregivers of males were more likely to suffer from anxiety symptoms, unlike previous studies. A previous study [61] found that female caregivers were more likely to experience psychological distress. The LASER-AD study found that being a female caregiver predicted having an anxiety disorder [67]. Our result might be because males are the core members of Chinese families; however, they are more impulsive and harder to control. Caregivers must take on more responsibilities (e.g., physical or financial problems) than before, which might result in caregiver’s anxiety symptoms.

We also found that care-recipient TEQ scores were a risk factor for caregiver’s depression symptoms. Previous studies have not investigated the relationship between empathy and depression symptoms. One possible reason might be that cognitive impairment is difficult to treat with either behavioral or pharmacologic methods, leading to embarrassment among care-recipients, which might contribute to caregivers’ feelings of social isolation.

In our study, some characteristics of caregiver (i.e., gender, education level, the caregiver’s working status, experience in caring for care-recipients with dementia, familiarity with the care-recipient and their relationship with the care-recipient) were not associated with caregiver’s anxiety and depression symptoms. Having less education was significantly associated with depression of caregivers of care-recipients with MCI in two [68, 69] of three studies [68‐70]. Caregiver gender [70‐72] and relationship with care-recipients [69, 70] did not predict depression of caregivers of care-recipients with MCI. Having less dementia knowledge significantly predicted depression of caregivers of care-recipients with MCI [70]. Depression of caregivers of care-recipients with dementia or cognitive impairment without dementia was associated with whether the caregiver was the care-recipient’s spouse, and whether the care-recipient had dementia or CIND [73]. The reason may be that we studied the anxiety and depression symptoms among caregivers of care-recipients with subjective cognitive decline and cognitive impairment, not only with cognitive function impairment.

To our knowledge, this study is the first to report the prevalence of and risk factors for anxiety and depression symptoms among the caregivers of care-recipients with SCD. The first limitation of our study is that the cross-sectional design limits any conclusions in a causal or predictive direction. Future work should examine these relationships longitudinally to more fully characterize the direction of cause and effect. Second, we adjusted for as many risk factors as possible in the logistic regression model; however, we can’t exclude the possible influence of uncollected risk factors such as the specific care time of caregivers, alcohol drinking habits, disease history (e.g., like head injury, coronary heart disease, hypertension and diabetes), economic status, physical and psychological illness among caregivers, and drugs that affect mental health. Third, there are only care-recipients with mild or moderate dementia, not the severe dementia in our study, but care-recipients with the severe dementia may cause serious impacts on their caregivers.

Our study suggests that clinicians should be aware of high rates of anxiety and depression symptoms among caregivers of care-recipients with SCD or MCI. We should also attend to the risk factors for anxiety and depression symptoms among caregivers such as care-recipient depressions, empathy and agitation. Furthermore, many caregivers require more social support via training as well as physical and mental health care. Such programs should provide caregivers with support to address their burden and educate them learn about cognitive impairment.