Researchers tested whether psilocybin could help postpartum depression in mice, but found it actually made things worse for both mothers and their babies. While psilocybin normally reduces depression and anxiety, it had the opposite effect during the postpartum period, making mothers more anxious and disrupting their care of pups. Babies exposed to psilocybin through breastfeeding or direct exposure developed anhedonia (inability to feel pleasure) as adults. These findings suggest that the postpartum period may be a particularly vulnerable time for psychedelic use, and more research is needed before considering these drugs for postpartum depression treatment.