title: How is an informal caregiver's psychological distress associated with prolonged caregiving? Evidence from a six-wave panel survey in Japan.
abstract: OBJECTIVE
  The provision of informal nursing care can adversely affect a caregiver's mental health, but the dynamic association of the variables is still under debate. We examined how an informal caregiver's psychological distress is associated with prolonged caregiving.
  
  
  METHODS
  We used data collected from a nationwide six-wave panel survey in Japan, with 25,186 observations of 9192 individuals. We focused on informal caregivers, who provided help and support for ill family members. We used Kessler 6 (K6) scores (range 0-24), where higher scores reflect higher levels of psychological distress. We employed mixed-effects models to examine how caregivers' psychological distress was associated with caregiving commencement and duration.
  
  
  RESULTS
  Commencement of caregiving raised the K6 score for female caregivers by 0.55 (equivalent to 0.12 SD, 95 % CI 0.34-0.75) and that for male caregivers by 0.41 (0.09 SD, 95 % CI 0.18-0.63). However, prolonged caregiving had gender-asymmetric, dynamic associations with psychological distress. One additional year of caregiving added 0.22 (0.05 SD, 95 % CI 0.10-0.35) to the K6 score of female caregivers, while it had no significant association for male caregivers. For female caregivers, prolonged caregiving was positively associated with K6 score entirely through its interaction effects with longer hours of care, co-residence with a care recipient, and the non-working status of a caregiver.
  
  
  CONCLUSIONS
  Results revealed a gender-asymmetric, dynamic association between informal care provision and caregivers' psychological distress. Additional policy measures targeted at caregivers deeply involved in in-house care are needed to reduce their distress.
authors.affiliation: Institute of Economic Research, Hitotsubashi University, 2-1 Naka, Kunitachi, Tokyo, 186-8603, Japan. oshio@ier.hit-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Oshio
mesh_terms: D000368:Aged; D017028:Caregivers / Q000523:psychology*; D005190:Family / Q000523:psychology; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D011788:Quality of Life / Q000523:psychology*; D013315:Stress, Psychological / Q000523:psychology*; D011795:Surveys and Questionnaires
keywords: Caregiver; Informal caregiving; Japan; Kessler 6 scores; Psychological distress