Concussions, whether from sports or from falls or motor vehicle accidents, are a tough problem for children, taking them far longer to fully recover than adults. But in a review of scientific research published recently in the British Journal of Sports Medicine, Australian researchers found that concussions can lead to mental health issues. The compiled research incorporated nearly 90,000 children who have had concussions in nine countries. They found that over one-third of children experienced significantly high levels of internalizing problems such as anxiety, withdrawal, depression and post-traumatic stress following a concussion. Another 20 percent experienced externalizing problems, like aggression, hyperactivity and lack of focus. And while their mental health generally improved between three and six months after the concussion, some children experienced lingering symptoms for several years.