A new study explains what many people suffering from depression already know – antidepressants are often not effective. Researchers at Northwestern University’s Feinberg School of Medicine say their findings prove that the medications are treating stress instead of the true cause of depression.

Long-time depression researcher Eva Redei says the team’s findings topple the common belief that stress causes depression.

Researchers studied the brain’s response to chronic stress in rats bred to be severely depressed. They compared stress-related genes and depression-related genes and found that there is almost no overlap between the two.

"This finding is clear evidence that at least in an animal model, chronic stress does not cause the same molecular changes as depression does," Redei said.

The results explain why antidepressants are considered ineffective so often as well. "The medications have been focusing on the effect, not the cause," she noted.

According to WebMD, alternative therapies like acupuncture, massage therapy, hypnosis and relaxation techniques are believed to be helpful in treating depression. Nutritional supplements containing St. John’s wort and gingko biloba as well as omega-3 fatty acids are also widely used.