A variety of studies in recent years have shown a correlation between television watching and depression. Some of these studies have suggested a cause and effect relationship between excessive television or television at certain times of day and the development of depression. Other studies have shown that certain television-related behaviors are symptoms of depression, and can be used to help diagnose mental illness. Watching Too Much Television A study published in 2011 in the American Journal of Epidemiology suggested that watching too much television can increase a person\u2019s risk of depression. From 1992 to 2006, 50,000 women participating in this study recorded their television watching and exercise habits, while noting any diagnoses of depression and any medication prescribed for depression. Other variables recorded by the participants in the study included weight, smoking habits and a range of diseases. The results of the data showed that the women who exercised 90 minutes or more every day were 20 percent less likely to have been diagnosed with depression. In contrast, the women who watched three hours or more of television per day were 13 percent more likely to have received a diagnosis of depression. Women are already twice as likely as men to suffer from depression. However, this study does not prove a definitive cause and effect relationship between television and depression. It may be that other habits common in people who watch a large amount of television\u2014such as generally sedentary habits and little exercise\u2014are the true risk factors for depression. Falling Asleep With the Television On A study from The Ohio State University Medical Center in 2012 suggested that late night television or falling asleep in front of the television could increase your risk for depression. The study looked at changes in the brains and the behaviors of hamsters that were exposed to dim artificial light at night. They found behavioral and biological indicators in the hamsters that have been connected with depression in humans. The behavioral changes that the researchers observed included less movement and activity, and less interest in drinking sugar water. The biological observations included changes in the hippocampus region of the brain that mirror changes in human brains during depression, as well as increased production of the protein tumor necrosis factor (TNF). TNF production increases when a part of the body is inflamed from illness or injury, and chronic inflammation is often present with depression. The researchers concluded that exposure to dim artificial light such as the light from a television might create changes in the brain if we are exposed to it late at night or while we are sleeping\u2014times during which the human body expects to be in darkness. They also found that (at least in the hamsters) a return to normal light\/dark cycles led to an eventual reversal in the symptoms. Teenagers and Television A study published in 2009 in the Archives of General Psychology looked specifically at depression and television watching in teenagers. Many parents, educators and other concerned individuals worry that the volume and variety of electronic entertainment in this day and age has resulted in young people spending too much time inside and inactive. They also worry that this may be having a negative effect on the mental health of children and teenagers. The researchers for this 2009 study examined data from 4,142 participants the National Longitudinal Study of Adolescent Health. They found that a teenager\u2019s risk for depression appeared to grown by 8 percent for each hour of television he or she watched per day. The researchers did not find the same results from other kinds of sedentary electronic entertainment such as video games or movies. The data was gathered between 1995 and 2002, before the rise of high-speed Internet and social networking sites. Like the 2011 study in the American Journal of Epidemiology, this data analysis does not clearly establish that significant television watching can contribute to the development of depression. It is possible that other major risk factors for depression also make teenagers more likely to watch more television. However, the greater risk of depression among those teenagers who watched more television compared to those who played more video games or watched movies does suggest that television, for reasons that are still a mystery, has a particularly strong connection with depression.