. Author manuscript; available in PMC: 2007 Aug 14.

Published in final edited form as: Brain Behav Immun. 2005 May;19(3):195–200. doi: 10.1016/j.bbi.2004.08.003

Table 1.

Summary of studies: interactions between optimism and stressor type predicted immune parameters

Study	N	Population	Stressor types	Outcome	Interaction effect size (r)
Cohen et al. (1999)	42	Caucasian women aged 18–45	Naturalistic: acute (<1 week) or chronic (>1 week)	%CD8⁺CD11b⁺	.27
				%CD8⁺CD11b⁻	.48
				NKCC	.31
Sieber et al. (1992)	55	Men aged 18–26	Experimental: control, perceived control, or no control	NKCC	.33
Segerstrom (2001); Study 1	48	Law students	Naturalistic: high or low goal conflict	# CD4⁺	.43
Segerstrom (2001); Study 2	22	Law students	Naturalistic: high or low goal conflict	DTH	.60
Segerstrom (2004)	46	Law students	Naturalistic: high or low goal conflict	DTH	.33
Segerstrom et al. (2003)	38	Medical and law students	Experimental: presence or absence of mental arithmetic task	DTH	.38

Note. For r, effect sizes of .10 are considered small; .30, medium; and .50, large.