Excessive television viewing leads to depression

A team of neurologists from the University of Ohio used hamsters to determine the connection between dim light at night and changes in behavior, and it turned out that the changes in the behavior and brain of the hamsters were similar to the symptoms of depressed people.

"The results in hamsters are consistent with what we know about depression in humans," said team leader Tracy Bedrosian. Although exposure to night light has been linked to an increased risk of breast cancer and obesity, the relationship between light and behavioral disorders has never been fully resolved, reports Reuters.

The animals participating in the experiment were exposed during the night to dim light equivalent to a television set in a darkened room for four weeks, and their results were compared with those of a control group that was not exposed to dim light at night.

The experimental group was then put into a normal cycle for Sunday, two or four before they were tested again. The results showed that the hamsters were less active and less interested in the sugar water - both signs comparable to signs of depression in humans.

Researchers have also discovered changes in the brain that are also associated with depressed people.

The hamsters also produced more of the protein TNF, a chemical messenger (neurotransmitter) that is mobilized when the body is injured or infected and causes inflammation in an attempt to repair the damage.

"Experts have found a strong link in humans between chronic inflammation and depression. That's why it's important that we find this link between dim light at night and increased TNFa secretion," said Randy Nilson who also worked on the study.

Symptoms of depression disappeared when the hamsters were returned to a normal cycle, and TNFa levels returned to normal after two weeks.

"The good news is that those who stay up late in front of the television or computer can reverse the harmful effects by returning to a regular day-night cycle and minimizing exposure to artificial light at night," Bedrosian said.