A CDC study released Wednesday showed that about one in 25 U.S. children ages 12 to 17 and one in 10 U.S. adults are taking antidepressants. The study was based on surveys and depression screenings of more than 12,000 U.S. adolescents and adults from 2005 to 2008. According to CDC, antidepressant use increased by nearly 400% during that period. The study found that antidepressants were the third most common drug used by people of all ages and the most common among individuals ages 18 to 44. Despite the high number of U.S. residents taking antidepressants, researchers noted that just one-third of survey respondents with symptoms of depression were taking medication, indicating that many people who are seriously ill are not receiving treatment.