Final answer:
The least common kind of maternal depression after delivery is postpartum psychosis, a rare but severe condition requiring immediate medical attention.
Step-by-step explanation:
The least common kind of maternal depression after delivery is postpartum psychosis. This severe mental health condition occurs in a small percentage of women and can include symptoms like delusions, hallucinations, and extreme mood swings. Compared to other forms of maternal depression, such as postpartum depression (PPD) and the more common but milder baby blues, postpartum psychosis is rare and requires immediate medical attention. Research, such as the studies by Wisner et al. (2013) and Halligan et al. (2007), emphasize the importance of early detection and treatment of postpartum depression to prevent worsening of symptoms and safeguard the health of the mother and child.