If you are feeling low, it may be best to lay off the fizzy drinks and have a cup of coffee instead.
A study has linked soft drinks to depression - with diet versions particularly problematic. Coffee, however, appeared to have the opposite effect.
The finding comes from US researchers who studied the drink consumption of 265,000 men and women aged 50 to 71.
A decade in to the study, the volunteers were asked if they had been diagnosed with depression in the previous five years.
Those who drank more than four cans of soft drinks a day were 30 per cent more likely to have had depression than those who drank none, the American Academy of Neurology conference heard. The risk seemed greater among those who preferred diet drinks.
The researchers said this may be due to the presence of the artificial sweetener aspartame, which yesterday was provisionally given a clean bill of health by the European Food Safety Authority, following a review.
Making the link does not prove soft drinks cause depression.
But researcher Honglei Chen said: "While our findings are preliminary and the underlying biological mechanisms are not known, they are consistent with a small but growing body of evidence suggesting that artificially sweetened beverages may be associated with poor health."
The study found that those who had four cups of coffee a day were 10 per cent less likely to become depressed than non-coffee drinkers. Dr Chen said this may be due to the caffeine in coffee stimulating the brain.
The British Soft Drinks Association urged caution over the findings and pointed out that the scientists themselves said that more research is needed.
Previous studies have linked soft drinks to heart attacks, diabetes, weight gain, brittle bones and pancreatic cancer.
- DAILY MAIL