People who use the Internet excessively are more likely to also have symptoms of depression, according to a study published online February 3 in the journal Psychopathology and reported by Reuters. The authors stress, however, that it is not possible to determine from the study results whether people who use the Internet excessively are more likely to be depressed, or whether depressed people are more likely to use the Internet excessively.

Researchers define Internet addiction (IA) as excessive use that leads people to neglect their work or social life, or to lose control over their Internet use, among other characteristics. To determine whether IA could be linked to depression, Catriona Morrison, MA, from the University of Leeds in the United Kingdom, and her colleagues conducted an online survey of 1,139 people. People were asked questions about their Internet use and common symptoms of depression.

Morrison and her colleagues found that 1.2 percent of the people surveyed met the definition of IA and that those individuals were more likely to have symptoms of depression than people who did not meet the IA definition. Participants defined as Internet addicts, on average, scored in the moderate-to-severe range of depressive symptoms, and the people without Internet addiction scored in the non-depressed range. Males were more likely than females to meet the IA definition, and younger people were more likely than older people to be defined as Internet addicts.

“Those who show symptoms of IA are likely to engage proportionately more than the normal population in sites that serve as a replacement for real-life socializing,” write the authors, who stated that additional research is needed to better characterize the relationship between IA and depression.

“Excessive Internet use is associated with depression, but what we don’t know is which comes first—are depressed people drawn to the Internet, or does the Internet cause depression?” Morrison told Reuters.

She warned, however, that “this type of addictive surfing can have a serious impact on mental health.”