A new study shows that children and young adolescents who take high doses of antidepressants early are more prone to suicide attempts than those who take typically prescribed lower doses.

The Food and Drug Administration has required antidepressant to show warnings that intake may increase the risk of suicidal thoughts and behavior in people below age 25. The study shows that the risk to deliberately harm themselves doubles when young people start to treat their depression with higher than recommended doses.

Previous randomized and controlled trials prompted the FDA to require the warning sign for antidepressants in young people. However, the warning remains controversial with scientists saying that the benefits of depression and anxiety treatment with SSRIs prevail over the increased risk of self harm and suicide attempts.

The study pulled information from a prescription database, including over 162,000 patients between the age 10 and 64 who had depression and started an SSRI medication between 1998 and 2010. Researchers focused on three of the most common antidepressants, Prozac, Zoloft and Celexa. The users were separated into two groups: those who took the prescribed dosages of the medications and those who took higher-than-prescribed doses. Patients who were prescribed more than one medication were not included in the study.

Around 18 percent of the 10 to 24 year olds in the research were recommended a higher dose but the reason why some were prescribed a higher dosage was unclear. It could be that those who were recommended to take higher than average doses of medication did not respond to lower dosages in the past. Patients younger than 24 who took higher dosages harmed themselves about twice the rate of the patients who took lower doses.

During the research period, 32 self-harm incidents were reported per 1,000 young patients who took high doses while only 15 incidents were reported for every 1,000 patients who took prescribed doses.

"One can quibble about how much benefit there is at typical doses, and my sense is that the benefit is modest at best," lead author of the study Matthew Miller said. "'But there's no evidence that higher initial doses are going to help more than lower doses.' Instead, higher doses may only add risk." Miller is also a physician at Harvard School of Public Health.