Several studies have found disruptions in cortisol awakening response in informal caregivers. Institutional support may modulate these effects, and this study analyses how the health of caregivers is affected when institutional support is provided for families of people with high-functioning autism. Self-reported health, depression and cortisol awakening response were analysed in three groups: supported caregivers, non-supported caregivers and non-caregivers. Non-supported caregivers presented higher somatic symptoms and lower cortisol awakening response than the supported caregiver and non-caregiver groups. A high number of somatic symptoms and low functionality of offspring were related to a lower cortisol awakening response only in the non-supported caregiver group. These findings demonstrate the importance of institutional support for improving the health of caregivers.