Upper estimate of Americans age 65 and older who have mental health or substance abuse conditions, according to a 2012 Institute of Medicine report.


The average number of genetic mutations in a child born to a 40-year-old father. A 20-year-old dad, however, only passes on about 25, according to a 2012 study in Nature. (See "Catching autism early")


Percentage of pre-teens and teens who have been bullied in the past year—an estimate far below rates found in past studies and common perception, according to a meta-analysis by Dan Olweus, PhD, of the University of Bergen, Norway.

4 times

How much more likely women diagnosed with attention-deficit hyperactivity disorder as girls are to attempt suicide when they are young women than those without ADHD, suggests a 2012 study in the Journal of Consulting and Clinical Psychology.