From Rob K Stefaniuk:

Re: Link between fast food, depression "confirmed" (April 2): The way the headline and story read it implies fast food may be responsible for depression. It really ought to convey the more likely, common sense, association that people who have lifestyle issues associated with depression are more likely to consume fast food. And that the malnutrition resulting from a prolonged fast food based diet can contribute to maintaining that condition. A subtle but substantial difference in tone I think is important to convey the correct message, IMO.

As a sidenote, I'm not a health professional, just someone interested and concerned with health issues and information presented to the public in a misleading or erroneous context. I think this story should either be reviewed and re edited or provided with more of a disclaimer if this is the intended conclusion the researchers would like to convey.