Since the start of the new millennium, more U.S. children are being labeled with disabilities than ever before.

A recent examination of national data on physical and mental disabilities in children shows that more kids had a mental or physical disability in 2011 than in 2002. And although rates of disability were greatest in poorer households, there was a surprisingly large increase in the prevalence of disability among children from wealthier families.

Overall, 16 percent more kids had disabilities. But the increase in the number of reported disabilities among children was not due to an increase in physical conditions. In fact, disabilities primarily related to a physical problem were down 12 percent during the study period. On the other hand, neurological or mental disorders rose by 21 percent. This category includes speech difficulties, learning disabilities, epilepsy and many more ailments.

That’s a whole lot of change for a relatively short period of time. The researchers who examined the data say it’s tough to know what’s behind all the shifting numbers. Factors could include everything from a greater awareness of neurological and mental conditions, to altered attitudes toward the conditions. The growing prevalence of disorders such as autism and attention-deficit hyperactivity disorder could play a role, too.

In addition, actual biological factors may be causing more of these cases.

Whatever is fueling the numbers, the trend present challenges for parents, health care providers, educators and politicians.

Learning how families and society can best serve these children will take time. Increasing our awareness and compassion for people with mental and neurological health problems is a great place to start.