Four states -- Vermont, Arizona, Alaska and Wyoming -- do not require any permit for a concealed weapon.
Gun sales surge, buybacks gain popularity
December set a record for the number of background checks for gun buyers during a single month, according to the FBI. It's an indicator of the rising sales of firearms.
And yet gun buyback programs have also gained popularity in Newtown's aftermath, with events springing up across the country, at times privately sponsored.
After the shootings at Columbine High School in Littleton, Colo., in 1999 and at Virginia Tech in 2007, calls for more school security sounded as the public sought to find ways to prevent mass violence from reaching students.
After the Newtown massacre, a similar phenomenon got under way as schools added cameras, locks and ran extra drills. And yet most schools already have some form of a functioning crisis plan, noted Kenneth Trump, a school security consultant.
"I don't believe we need to throw out the book of best practices on school safety," he said. "I think we do need to focus our resources, times and conversation back on the fundamentals."
In their effort to protect both patients and the public, health advocates are calling on legislators to take a closer look at the nation's mental health care system in the wake of the Newtown tragedy.
And a glance at the numbers offers some insight into the extent of the issue.
One quarter of adults suffer from a "diagnosable mental disorder in a given year," while 6 percent of U.S. adults have what can be considered a "serious mental illness," according to the National Institute of Mental Health.
Research conducted at the Centers for Disease Control also indicates that 3.4 percent of noninstitutionalized adults suffer from "serious psychological distress" in a given month.