Over the weekend a little case study popped up on pubmed. Free full text paper, voila:
A case study of cola dependency in a woman with recurrent depression
It's not the world's greatest paper. It's a simple case study, just an introduction that proves nothing. The most fascinating thing about the paper is what we don't know about the consumption of cola, addiction, and mood.
So let's jump in. There is a 40 year old woman who has been on antidepressants for many years, and in addition drinks up to 3 liters of soda every day. She craves soda of a particular brand and has been unable to cut down her consumption in spite of the fact that it is probably interfering with her sleep, and she's developed metabolic syndrome. She feels the soda gives her an energy and mood boost. In fact she meets official criteria for dependence (which are official and written out and require physical dependence and withdrawal syndrome among some other symptoms, but what it all boils down to is continued use despite harm). After a serious exacerbation of her depression, she is referred to an outpatient clinic for treatment.
They work on slowly reducing her soda consumption. Low and behold, she sleeps better, feels better, has better energy, and her depression gets better. She still drinks a bit of soda, but not the massive amounts. She loses weight and stops having metabolic syndrome. She was able to wean off her antidepressant medication and felt good. Success.
So the interesting thing about the paper is what they weren't able to find. There is absolutely nothing in the literature about cola dependence. Nada. Earnest pubmed search comes up empty. And I have several patients with medical issues due to excess calories and sleep problems who overconsume cola to an enormous degree. I myself once drank diet coke daily, and if I skipped a day, would have intense cravings for it, and upon imbibing it I would feel instantly better.
The only "science" the researchers could find was a poll from a Danish radio station, where 16% of 1006 participants considered themselves to be addicted to cola (there is a link in the paper to a website, but it is in Danish). The paper really only considers a sugar/caffeine combo as addictive as part of a reason it might be related to a resistant depression. Of course, caffeine in the form of coffee has actually been associated multiple times with less depression. There is a bunch of literature on that. I have some other theories:
1) Soda in the context of the very common issue of fructose malabsorption could potentially cause inflammation and depression. See: Could Sugar and Soda Be Causing Your Depression?
2) Soda as a source of many empty calories will more than likely compromise micronutrition. See: Soda Begets Zombies
I mean, it is an interesting question. No one is homeless or in jail because he or she squandered all his or her life savings and relationships for the pursuit of soda. But it doesn't take that much imagination to see some very bad long term medical consequences… and the psychiatric consequences desperately need further study. Frankly it boggles the mind that soda is so novel and ubiquitous yet we know so little about how it affects the brain.
Happy New Year!