Worries about a link between depression and the amount of time spent on Facebook or other social media sites are probably unfounded, a US study said this week.

The University of Wisconsin School study found no basis to support the theory outlined in a study last year by the American Academy of Pediatrics that suggested exposure to Facebook could lead to depression among adolescents.

"Our study is the first to present scientific evidence on the suggested link between social-media use and risk of depression," said Lauren Jelenchick, a researcher at the UW School of Medicine and Public Health.

"The findings have important implications for clinicians who may prematurely alarm parents about social-media use and depression risks."

Jelenchick and professor Megan Moreno surveyed 190 students at the university between the ages of 18 and 23. The survey participants were on Facebook for over half of the total time online.

They found no significant links between social media use and the probability of depression. The results were published Monday in the Journal of Adolescent Health.

"Our findings are similar to those from studies of other communication applications, such as e-mail and chat, which also found no association with depression," the researchers wrote.

Still, they noted that "a single study cannot prove or disprove an association" and cautioned that the latest study "is limited by the sample's ethnic homogeneity, our focus on older adolescents in a single university setting, and a small sample size."

Moreno, a pediatrician who studies social media use among children and adolescents, said parents don't have to be overly concerned if their child's behavior and mood have not changed, and if they have friends and their school work is consistent.

"While the amount of time on Facebook is not associated with depression, we encourage parents to be active role models and teachers on safe and balanced media use for their children," said Moreno.