The consensus among sleep specialists is that there are roughly six stages of sleep regression at different ages—when the baby is 4, 6, 8, 12, 18, and 24 months old. While sleep regression is a common ...

In statistics, a mathematical method of modeling the relationships among three or more variables. It is used to predict the value of one variable given the values of the others. For example, a model ...

Age regression is an unconscious return to an earlier stage of behavioral, emotional, or social development. It can be a sign of distress, trauma, or a mental health condition. Temporary age ...