Although
none of the groups reported on drug side effects, while Guo who tested only breastfed infants reported on significant decrease in infant crying, and decrease in depressive
symptoms at one month and at two months respectively, Sung who tested both formula fed and breastfed infants reported on increase crying in the probiotic treated infants (particularly in the formula fed infants)
compared to placebo with no effect on maternal depressive
symptoms.