title: A systematic review of the psychobiological burden of informal caregiving for patients with dementia: Focus on cognitive and biological markers of chronic stress.
abstract: As the physiological impact of chronic stress is difficult to study in humans, naturalistic stressors are invaluable sources of information in this area. This review systematically evaluates the research literature examining biomarkers of chronic stress, including neurocognition, in informal dementia caregivers. We identified 151 papers for inclusion in the final review, including papers examining differences between caregivers and controls as well as interventions aimed at counteracting the biological burden of chronic caregiving stress. Results indicate that cortisol was increased in caregivers in a majority of studies examining this biomarker. There was mixed evidence for differences in epinephrine, norepinephrine and other cardiovascular markers. There was a high level of heterogeneity in immune system measures. Caregivers performed more poorly on attention and executive functioning tests. There was mixed evidence for memory performance. Interventions to reduce stress improved cognition but had mixed effects on cortisol. Risk of bias was generally low to moderate. Given the rising need for family caregivers worldwide, the implications of these findings can no longer be neglected.
authors.affiliation: APC Microbiome Institute, Biosciences Institute, University College Cork, Cork, Ireland; Department of Psychiatry & Neurobehavioural Science, University College Cork, Cork, Ireland.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Allen
authors.affiliation: The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland; Department of Epidemiology & Public Health, University College Cork, Cork, Ireland.
authors.forename: Eileen A
authors.initials: EA
authors.lastname: Curran
authors.affiliation: School of Medicine, University College Cork, Cork, Ireland.
authors.forename: Áine
authors.initials: Á
authors.lastname: Duggan
authors.affiliation: APC Microbiome Institute, Biosciences Institute, University College Cork, Cork, Ireland; Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland.
authors.forename: John F
authors.initials: JF
authors.lastname: Cryan
authors.affiliation: Centre for Gerontology & Rehabilitation, University College Cork, Cork, Ireland.
authors.forename: Aoife Ní
authors.initials: AN
authors.lastname: Chorcoráin
authors.affiliation: APC Microbiome Institute, Biosciences Institute, University College Cork, Cork, Ireland; Department of Psychiatry & Neurobehavioural Science, University College Cork, Cork, Ireland.
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Dinan
authors.affiliation: Centre for Gerontology & Rehabilitation, University College Cork, Cork, Ireland.
authors.forename: D William
authors.initials: DW
authors.lastname: Molloy
authors.affiliation: The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland; Department of Epidemiology & Public Health, University College Cork, Cork, Ireland.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Kearney
authors.affiliation: APC Microbiome Institute, Biosciences Institute, University College Cork, Cork, Ireland; Department of Psychiatry & Neurobehavioural Science, University College Cork, Cork, Ireland. Electronic address: G.Clarke@ucc.ie.
authors.forename: Gerard
authors.initials: G
authors.lastname: Clarke
mesh_terms: D015415:Biomarkers; D017028:Caregivers; D003071:Cognition; D003704:Dementia; D006801:Humans; D013315:Stress, Psychological
chemical_list: D015415:Biomarkers
keywords: Attention; Biomarker; Cardiovascular; Caregiver; Cognition; Cortisol; Dementia; Epinephrine; Immune system; Memory; Norepinephrine; Stress