The mind and the gut are tightly connected. Anyone who's had a stomach ache accompany a bout of nervousness can testify to the phenomenon. A study in rodents now suggests that digestive troubles early in life may even predispose people to developing anxiety and depression.
Previous studies have shown that people who have chronic stomach aches are more likely than other people to be anxious or depressed. In the new study, researchers at Stanford, UC San Francisco and the University of Kansas looked at whether the stomach ailments could causes mood disorders instead of what is presumed: that emotions cause stomach problems.
Researchers caused mild stomach irritation in 10-day-old rats for six days. When the behavior of the rats was assessed when they were 8 weeks to 10 weeks old, researchers found the rats with early stomach problems were much more likely to exhibit anxious and depressed behavior. They consumed less sugar water, swam less and preferred dark areas rather than light areas. They also had higher levels of several stress hormones.
The early stomach woes "might also be effecting the development of the central nervous system, and driving the animals to anxiety and depression," the senior author of the study, Pankaj Pasricha, chief of gastroenterology and hepatology at Stanford University School of Medicine, said in a news release. "It seems that when the rats are exposed to gastric irritation at the appropriate time there is signaling across the gut to the brain that permanently alters its function."