They found that those drinking 4 or more cans of soda a day were 30 percent more likely to have been diagnosed with depression than those who didn't drink it.
And the risk was even higher for those who drank diet soda.
For those drinking fruit punch, there was a 38 per cent increase in depression risk.
By contrast, 4-cup-a-day coffee drinkers were about 10% LESS likely to be diagnosed with depression.
Critics says it doesn't prove soda plays any role in depression, or whether other factors may be the culprit.