Monday, December 31, 2012

Cola, Depression, and Addiction

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!


  1. Soda is unique in several regards. Several people I have assessed consume large amounts of soda and tell me that they got into the pattern instead of drinking water. If you search "sweeteners and addiction" there are several interesting studies at both the clinical and basic science levels:

    I think that the whole area of food additives and flavorants at the industry level is probably aware of this phenomenon and they use it to sell more product.

    Tried any of the wild cherry flavored products lately? They can be addictive.

    Happy New Year

    1. Yes, I should have discussed the addictive aspects of caffeine and sugar more… and there is a literature on that. However, I think the particular mix of fizzy, sugar (or aspartame), and caffeine is a different animal. It is relatively straightforward to kick a coffee habit. Mix up with decaf, slowly reduce the added sugar, in a few weeks things are okay. Soda is a whole different animal. Mostly I've had success switching people over to club soda + lime for at least some of the glasses throughout the day, and asking people to buy smaller bottles (going from two liters to purchasing one 20 oz at a time). But a few days of slipping and they are back at square one.

      And re: cherry flavoring… I had to stop drinking sugar soda in my late teens because I would predictably get a sugar crash about 90 minutes after drinking it. I switched to diet, though when I tried some of the *diet* cherry flavors they would do exactly the same thing. Even regular diet Dr Pepper started to cause it after a while (Dr. Pepper has strong cherry flavor notes). Normal diet coke does not do it.

  2. There is something very attractive in a carbonated water. I just love club soda. I don't drink liters of it everyday, sometimes it is in my fridge, sometimes it is not, but the sensation in my mouth when I drink it could be described as an intense pleasure.

    1. Agreed. Though I don't have people who drink 3 liters of soda water a day. And since it is hard to imagine soda water causing too much harm (other than GI discomfort) it's hard to use the "continued use despite harm" definition with club soda, thus it would be difficult to be "addicted" to it in the clinical sense. But I do think the addition of fizz to the caffeine and sugar is important, and that's why I think more studies should be done on soda (sugar and diet) and addiction, cravings, etc. just to elucidate the situation more clearly.

  3. Dr. Dawson: Exactly. To assume that this is some regrettable accident is naive.

    I feel the same way about statins. And wheat.

    But we are all on our own, so to speak, in terms of figuring these things out, and in dealing with the "industry" that creates the misinformation and subsequent metabolic issues, but the information we need to figure it out is right in front of us. The mainstream media is in the grip of these people, as are the various governments.

    I also know people who start the day with two diet cokes, and continue on with the stuff all day long. They assume it is harmless.

    "Food" that comes from factories has to be viewed with suspicion.


  4. I even think sugar and coffee can have bad long-term consequences. Making a habit out of breakfasting with just lots of sugared coffee, as I did for many years, tends to screw up blood sugar regulation and natural hunger swings, prompting one to make bad food choices for lunch and dinner and midnight snack.

    Soda, with it's higher sugar content, HFCS, and lower caffeine has greater capacity for addiction and being a food/water replacement. I mean one can only get so many empty calories from sweetened coffee before one hits the caffeine wall. Depending on one's caffeine tolerance and overall sugar consumption, there's probably a sweet spot of the addictive properties of a sugar/caffeine combo, and I'm guessing Coke is pretty near that average sweet spot.

    1. Yes, I imagine coke is that perfect sweetness for teenagers (who like things a little sweeter than adults). Little children (or at least my children) don't like fizzy drinks. They always wrinkle their noses.

      And I'm not suggesting coffee is innocent (particularly sweetened coffee) though the literature is surprisingly beneficent to high coffee consumption and health (a lot of of these studies are in Scandanavian countries where people drink strong coffee all day long…I'm sure it's not a Starbucks mocha frap, however)

    2. I think that coffee probably has a net positive effect on people with high to normal tolerance. But combined with sugar can turn into a definite negative. And then there's powdered creamer *shudders* although that seems to have mostly disappeared these days.

      In my case, more than half a cup is counter-productive--and I mix that with plenty of heavy cream. It's fun to get amped-up and bounce off the walls but crashing is not worth it, nor is turning into an ADD squirrel. My mother has a similarly low resistance and I've tried to convince her to dial back the coffee, but whatchagunnado ay?

      It does make sense that the sweet spot of soft drinks is aimed at a teenage palate.

  5. Here's one data point on this:

    I strongly suspected that diet coke played a role in my depression. I was drinking ~2 cans a day. I quit the stuff because of concerns of how it would affect my susceptibility to insulin resistance and accidentally discovered that its removal lifted my mood considerably. But it took 4 weeks of cold turkey before the cravings stopped. I really had no idea how much I was addicted to the stuff until that point. Who'd of thought that just 2 cans a day would have such a strong impact? I appreciate that others have not felt similar withdrawal affect but clearly some of us react this way...

    1. It took me a Whole30 to kick my near daily diet Coke habit, a year into "paleo" eating. The cravings were intense. Some of my patients who have done Whole30s tell me that the cravings for diet soda are worse than those for cheese or alcohol. I find that fascinating. Even this morning, when I woke up with a mild headache (thanks to last night's champagne no doubt, Happy New Year), my very first thought was of a diet coke, and I haven't had one in a while.

  6. Coca-Cola back in the early days contained cocaine. Hmmm...

    Thanks for sharing this case report.

    I hope 2013 is a great one for you, Emily. BTW, I like your new twitter avatar; makes you look about 10 years younger, too.


    1. Thanks, Steve! You too! If it still contained cocaine we might have more studies about it :-)

  7. Here's another oddball hypothesis that popped into my head (sorry about the pun). It regards an application of Seth Robert's theory (articulated in the Shangri La Diet) about flavor-calorie Pavlovian associations. The gist of the theory is that pairing a flavor with calories creates an association between them (with the flavor serving as the Pavlovian CS and the caloric effects on the body the US). The more often the flavor is paired with the calories, the stronger the association (up to an asymptotic level, presumably). The strongest associations tend to develop between a salient, unique flavor (e.g., soda, donuts, little debbie snacks, doritos, etc.) that are VERY similar each time they are consumed (what Seth calls "ditto foods"). What consumption of a ditto food does, according to the theory, is to raise the body weight (or fat mass) set point. If the consumption of ditto foods is to such an extreme level, such as a dependence-level intake of soda, then the set point is continually being raised and probably hovers above the actual set point. What does this create? A body that "thinks" it's at a calorie deficit. What does the body do on a calorie deficit? Goad the individual to seek and consume more calories and reduce energy expenditure. It is the latter that could, chronically, perhaps account for the depression (in addition to the stress induced by being at constant "starvation"). I'm not suggesting this is the only account, or mutually exclusive of others, but the details of Seth's theory seem to fit an emerging picture that explains many disparate phenomena regarding food seeking and consumption on the one hand and physical and mental health on the other.

    Happy New Year!

  8. My anecdote:

    -When I was a teenage fatass I drank a lot of soda but mostly I drank fruit juice. My addiction was juice. I craved juice. Anything sweet, fruity, it needed drinking. I did not like things which were too sour or acidic so I didn't like orange, and I didn't like cola quite as much. I liked fruit juice, and I liked canned iced tea/sprite/similar fruity sodas. I had no response to caffeine at this time probably due to zero dopaminergic tone/chronic depression and was apathetic to anything caffeinated. Never responded to coffee or coke with any energy.

    -When I lost weight I became hypersensitive to caffeine, and sensitivity to caffeine correlates with weight loss/food restriction. I stopped preferring iced tea and sprite and developed a strong preference for coffee and coke (diet of course). As I began eating more and gaining weight my sensitivity to caffeine has gradually diminished, probably reflecting a more normal dopamine sensitivity. People still tell me I'm wired & hyper much of the time, however.

    -I never had a coke addiction although I did start to "prefer" coke and drank about 1-2 cans per day of DC. Several months ago I ran out of diet coke and merely stopped drinking soda ever again, never to return. Don't miss it, don't crave it. I get my caffeine from coffee, strong brewed green tea flavored with sugar free fruit juice packets, and the occasional diet rockstar.

    The concept of "coke addiction" fascinates me. Outside of a caffeine habit which can be satisfied by any tablet powder or drink, it seems there are people specifically addicted to coke. I tend to assume it is phenylalanine which metabolizes into dopamine and inhibits serotonin, which perhaps some people turns them addicts.

    In the past when drinking diet soda I was very aware of it and I was careful not to overdo because of the caffeine. It also made me feel gross and yuck when I drank more than 1 or 2 cans. I have no idea how anyone can drink more than 2 cans a day w/o feeling like a disturbed person.

  9. Emily, I think you're on to something of extraordinary importance here. There's something in soda (including diet coke) that is incredibly addictive.

    I think it's a huge story -- a central element of the obesity epidemic, hiding in plain sight.

    I hope you'll keep looking into it.

  10. Coca cola is still flavoured with Erythroxylum Coca extract. The cocaine has been removed... but who's to say there aren't other, more subtly addictive psychoactive tropanes left behind? The original restrictions on alkaloids in Cola and processing methods used may be outdated.
    "Besides coca, the coca leaf contains a number of other alkaloids, including methylecgonine cinnamate, benzoylecgonine, truxilline, hydroxytropacocaine, tropacocaine, ecgonine, cuscohygrine, dihydrocuscohygrine, nicotine and hygrine."

  11. "After 1904, instead of using fresh leaves, Coca-Cola started using "spent" leaves – the leftovers of the cocaine-extraction process with trace levels of cocaine.[40] Coca-Cola now uses a cocaine-free coca leaf extract prepared at a Stepan Company plant in Maywood, New Jersey."

  12. This was a very interesting post. I have chronic (recurrent) major depression and over the last two years developed increasing cravings for Coca Cola, because it appears to be the only substance which lifts the psychomotor retardation temporarily; neither coffee nor anything else appear to have the same effect.

    I had my first depressive episode 20 years ago, but my "addiction" only set in after starting psychotherapy two years ago, when the symptoms of depression began to get better. Since I am afraid of possible negative effects on my health, I limit myself to two glasses per day and drink water the rest of the time, but there is no denying that I would consume a lot more if I just gave in.

  13. I have searched for assays or legal or FDA details of decocainated coca extract without success.
    Which is odd as I'd expect the FDA to be all over it. Some old backroom deal which no-one has the power to challenge, perhaps.
    Just this:

    Some people can be very sensitive to cocaine. The addiction to Coca Cola could be a kind of allergic sensitivity to trace amounts. Potentiated of course by fructose - the gateway drug.

    Heads up:

  14. I do not know is this news article made it into the news in the USA... BUT when I saw this it reminded me of this post of yours...

  15. Good article. Soda addiction is harmful and can lead to a future filled with chronic pain and disease.

  16. We know it wasn't a great paper ;) And you've caught our point very accurately… Why is there no research on this subject, when cola addiction seems to be a publicly accepted phenomenon?
    An interesting detail is that biomedcentral wouldn't let us write Coca-cola. The editor asked specifically for us not to mention the brand name… One of the important points in this case report was the patients addiction to one specific brand AND flavor. She could under no circumstance substitute the Coca-cola soda, for any other brand or flavor…


Tired of receiving spam comments! Sorry, no new comments on the blog

Note: Only a member of this blog may post a comment.