Diet Soda and Depression

I have mentioned before the tendency of journalists and the media to try to get and hold our attention with emotionally charged pictures or stories.  We regularly see news about the results of studies that seem surprising, scary, or shocking, but are usually somewhat meaningless.  They challenge our ability to remain calm and think rationally about the subject.  Here is another example.

“A new study finds that people who drink diet sodas or fruit drinks are more likely to be diagnosed with depression.”  The article continues very responsibly to explain the size and nature of the study and to emphasize that a link does not necessarily mean that drinking diet sodas causes depression, but the headline - Drinking diet soda linked to depression – has us hooked.  (With sugary soft drinks being blamed for obesity - blame the soda, not the person drinking it - our choices are narrowing.)

Thinking critically about it, we know that correlation is not the same as causation.  "Linked to" isn't the same as "caused by."  We may wonder what we are supposed to do with this information – stop drinking diet soda so to avoid depression or start drinking lots of coffee, which the article tells us may have the opposite effect?  I don’t think it works that way.

Later in the article they say, “more research is needed.”  So what was the point?

Why should we even care about these kinds of studies that give preliminary findings, or publicize findings before they are presented for formal review, or rely heavily on self-reporting as opposed to objective observation?  As I pointed out before, we don’t have the time or energy to be worried about everything, so there is nothing really useful about such news.  But it does make for catchy headlines.