Review: exploration of psychological and physical health differences between caregivers and non-caregivers.

Study selection and analysis: Eligible studies compared levels of perceived stress, depression, general subjective well being, physical health, or self-efficacy between a sample of informal caregivers of older adults and a sample of non-caregivers. Exclusions: studies where reported differences between caregivers and non-caregivers could not be converted to standard deviation units (see notes); not written in English, French, German, or Russian.