Fighting in front of the kids makes them crazy: literally.
Researchers at the University of East Anglia in Norwich, England, tested the brains of 58 teenagers who had been exposed to "mild to moderate" family problems before age 11. Kids who faced such problems had a smaller cerebellum than those not similarly exposed.
The cerebellum is involved in stress regulation, skill learning and sensory control. Kids exposed to arguing pre age-11, therefore, are at higher risk of developing mental disorders.
Kids exposed to problems after age fourteen, however, ended up doing relatively better on the researchers' scans. The study authors surmize that kids have more mental coping skills at that age and dealing with their parents' frustrating arguments may actually help them tune out background stress.