['No longitudinal studies have addressed the effect of late life depression on the physical and mental health status of their informal caregivers.', 'To examine whether a diagnosis of depression in older medical inpatients is associated with the physical and mental health status of their informal caregivers after 6 months, independent of the physical health of the care recipient.', 'Longitudinal observational study with 6-month follow-up.', 'Two Montreal acute-care hospitals.', 'A sample of 97 cognitively intact medical inpatients aged 65 and over and their informal caregivers, with oversampling of patients with a diagnosis of major or minor depression.', 'Patient data included depression (current diagnosis, duration of current diagnosis, severity of symptoms, and history of depression), physical health (severity of illness, comorbidity, premorbid disability), and cognitive impairment. Caregiver data included relationship to patient, co-residence, and the physical and mental health status subscales of the SF-36. Multivariate linear regression analyses were conducted to determine the relationship between patient depression and caregiver 6 month SF-36 physical and mental scores, adjusting for baseline values, patient comorbidity, disability, and other patient and caregiver variables.', 'Patient characteristics included: mean age 79.3, 62% female, 46% major depression, 18% minor depression, 36% no depression. Caregiver characteristics included: 73% female, 35% co-resident spouse, 15% other co-resident relation, 50% not residing with the patient. Results of the multivariate analyses showed that in comparison with caregivers of patients without a current diagnosis of depression, caregivers of those with major depression had a lower mental health score at follow-up (-9.54, 95% CI -16.66, -2.43), even though their physical health was slightly better (5.42 95% CI 0.04, 10.81).'] Does major depression among medically ill elders contribute to sustained poor mental health in their informal caregivers?