Comment on "Stress in puberty unmasks latent neuropathological consequences of prenatal immune activation in mice"

Giovanoli et al. (Reports, 1 March 2013, p. 1095) applied an immune challenge to pregnant females, and therefore to all offspring, and subsequently applied stress to offspring on a per cage basis. The data, however, were analyzed as a completely randomized design, which is inappropriate given these restrictions on randomization. This will increase both false positives and false negatives.