By Margarita Nahapetyan
Teenagers who are greatly exposed to TV and other electronic media, highly raise the risk of developing depression in young adulthood, especially men, according to a new U.S study.
Dr. Brian A. Primack, of the University of Pittsburgh School of Medicine and his colleagues conducted a study, which began in 1995, and analyzed the television viewing habits of 4,100 healthy adolescents. The participants were asked how many hours per day they spent watching TV, playing video games or listening to the radio (the survey was conducted before DVDs or the Internet became widely available), during the past seven days. None of the adolescents had symptoms of depression at the beginning of the study.
The adolescents reported an average of 5.7 hours of media exposure each day, including 2.3 hours of television viewing, 0.6 hours of video cassettes, 0.4 hours of computer games and 2.3 hours of listening to radio.
Seven years later (at an average age of 22 years), all the participants underwent screening procedure and it was found that 308 (7.4 per cent) teenagers had developed symptoms consistent with depression. According to the report, published in the Archives of General Psychiatry, for each extra hour of TV viewed each day, the adolescents had a significantly greater chance of developing depression in young adulthood. "In the fully adjusted models, participants had significantly greater odds of developing depression by follow-up for each hour of daily television viewed," the authors wrote.
Given the exact same amount of media exposure, young women were less likely to develop symptoms of depression than were young men.
There are many possible ways through which media exposure could increase the risk of depression, the researchers said. The time spent watching television or engaging in other electronic media may be replacing time spent with friends or family, as well as intellectual or sport activities - all of which may protect against depression.
The most damaging part of media exposure is the one that occurs at night, the researchers emphasized, because that is the time when teenagers are supposed to be in bed, instead of watching television or playing video games. Exposure to media at night may disrupt sleep, which is important for normal mental and emotional development. In addition, messages transmitted through the media may reinforce aggression and other risky behaviors, interfere with identity development or inspire fear and anxiety, stated the authors.
According to background information in the article, depression commonly begins in adolescence or young adulthood, and is the leading cause of disability worldwide. "The development of depression in adolescence may be understood as a bio-psychosocial, multifactorial process influenced by risk and protective factors including temperament, genetic heritability, parenting style, cognitive vulnerability, stressors (e.g., trauma exposure or poverty) and interpersonal relationships," the authors wrote. Media exposure is another apparent influence, since teens are exposed to an average of eight and a half hours of electronic media each day.
However, Dr. Primack, said that the results did not prove that watching of TV was absolutely a cause of depression. "It could be argued that people with the predilection for later development of depression also happen to have a predilection for watching lots of TV." But the circumstantial evidence suggesting that TV was the culprit was very strong, he said.
The study also did not look at what content the kids were watching, which is believed to have huge effects. Nor did it analyze whether the contents were appropriate for the age. None of the teenagers in the original study was asked all those questions. Dr. Primack plans to start a new investigation that will add content into the equation.