Smyth, J. M. (1998). Written emotional expression: Effect sizes, outcome types, and moderating variables. Journal of Consulting and Clinical Psychology, 66(1), 174-184.
A research synthesis was conducted to examine the relationship between a written emotional expression task and subsequent health. This writing task was found to lead to significantly improved health outcomes in healthy participants. Health was enhanced in 4 outcome types—reported physical health, psychological well-being, physiological functioning, and general functioning—but health behaviors were not influenced. Writing also increased immediate (pre- to postwriting) distress, which was unrelated ...