Caregiver Stress and Sleep Study

Depression symptoms are a major public health concern in family dementia caregivers (dCGs) with shared risk factors. With more people living with dementia in the coming decades, more people will become unpaid dCGs. Replacing dCGs with skilled workers is untenable and would cost an estimated $162 billion annually. An estimated 1 in 5 dCGs have a depressive disorders. Over periods of 1-2 years, studies estimate that 25-48% of dCGs will develop new clinically significant symptoms or disorders. Depression symptoms relate to poorer quality caregiving and have health implications, including increased risk for physical function decline and chronic disease mortality. Especially when other risk factors are present, depression symptoms increase the likelihood that symptoms will worsen and disorders emerge. As in older adults generally, the recent National Academies of Sciences, Engineering, and Medicine report "Families Caring for an Aging America" states that the impact of caregiving on mental health is "highly individual," i.e., allocated to caregivers with vulnerability factors. This study focuses on one such vulnerability, morning activation deficits (MADs), based on evidence that MADs are a promising modifiable target for precision depression interventions in dCGs.

Investigators recently observed that MADs predict the depression symptoms persistence, independent of other key factors in dCGs. Data from dCGs shows that the relationship between MADs and depression symptoms involves heightened resting-state amygdala-posterior cingulate connectivity. In the context of prior literature, this implicates rumination. Given that bi-directional relations are plausible, controlled experimental data are needed to determine if targeting morning inactivation influences depression's mechanisms. If so, this would confirm MADs as a clinically actionable intervention target for controlling associated depression mechanisms.

Investigators piloted targeting MADs by using activity scheduling and monitoring, the logically relevant component of existing approaches, which is called Scheduling Activity and Monitoring Mornings (SAMM). MADs are defined as difficulty "getting going" and related objective morning inactivity. The SAMM protocol aims to increase the ease/level morning activity engagement by making, scheduling, and monitoring a morning action plan. Pilot data demonstrates that SAMM engages the target (MADs) and affects mood. This support the feasibility of using SAMM to probe effects of target modification on the hypothesized (ruminative processes) and alternative pathways. Tracking effects of modifying MADs with multi-modal data will elucidate how MADs may contribute in depression's mechanism. This randomized controlled study is needed to determine if SAMM has causal effects apart from non-specific therapeutic effects. Results will indicate if/how targeting MADs with SAMM could be pursued in precision efficacy trials.

Investigators are not proposing a prevention or treatment efficacy trial. The overarching aim is to delineate a mechanism that investigators propose operates across continuums of depression severity, risk, and resilience. Aim 1 will compare dCGs selected to be on either end of a spectrum: dCGs with MADs at levels linked with depression symptoms versus "morning type" dCGs who habitually prefer morning activity engagement. This provides a window into the mechanism by which MADs predict depression symptom persistence, while being a "morning type" appears protective. This contrasts with the designs of depression risk/incidence, prevention efficacy, and treatment efficacy studies; such studies select participants based on depression thresholds, which here, would restrict natural variability in (and bias estimates of) the mechanism of interest. This contrasts with case-controlled studies that compare people with/without depression (regardless of morning activation); such designs could add mechanistic heterogeneity and divert signal from the process by which MADs relate to depression symptoms.

Aim 1 (observing mechanistic differences comparing ends of the MAD exposure spectrum): To characterize differences between dCGs who have MADs, compared with "morning type" dCGs, with regard to: (A) daily patterns rumination and mood symptoms; (B) resting-state connectivity; and (C) rumination cue-related activation.

Hypotheses: The group with MADs will have relatively (A) greater rumination and depression symptoms; and (B) greater resting amygdala-PCC connectivity; and (C) exaggerated limbic, DMN, and FPCN responses to rumination cues.

Additional model testing: Unique from concurrent correlations, MADs will predict later rumination and depression symptoms.

Aim 2 (modifying target): Among dCGs with MADs, test the effects of an active experimental probe targeting morning activity engagement (SAMM), compared with a contact-time matched control condition, on self-reported and actigraphy measured MADs.

Hypotheses: Relative to the control condition, the active probe will be associated with decreased self-reported MADs and increased actigraphy-measured morning activity.

Aim 3 (modifying mechanism via target): (A) Test effects of the active vs. control probes on EMA-measured rumination, resting-state connectivity, and brain network responses to rumination cues. (B) Evaluate if the probe's effects are explained by increases in morning activation.

Hypotheses: SAMM (vs. control) will be associated with reduced rumination and changes in the biomarker pattern listed in Aim 1.

Additional model testing: Experimental effects will be mediated by morning activation increases.