Q:  Breath Odor & Depression

I too have noticed my bipolar wife's breath smells bad when she's severely depressed. I'm certain that there is something related going on here because her breath is always un-noticeable when she's on an even keel, but once she gets depressed, there is a very prevelant odor.  Does the body send out breath odor to indicate that there's too much or too little of a certain nutrient?  Could it be something as simple as say for instance, more salt is needed in her diet?


Dear Mr. H' 
Spouses and other close family members can often tell "something's different" when a person's mood/energy changes with bipolar cycling, so I wouldn't ignore what you're describing, although I've never heard this one.  I doubt that it's something as simple as a "missing nutrient" signal, but who knows? We still don't have a good chemical explanation for bipolar cycling -- as opposed to depression alone, where the molecular explanations are getting very far along; I'd urge you to see what that looks like, for comparison; here's an attempt to show how much is already understood, in plain English, about the brain chemistry of depression.

To speculate about what's going on here: I suppose when she gets depressed she might eat less, perhaps little? When people are consuming less than what they're burning every day, especially if it is a lot less, they become "ketotic": they start releasing fuel molecules into the blood called "ketones", from their fat stores.  Ketones diffuse easily from the blood to the air in your lungs, and they have a very noticeable odd odor, sometimes described as sort of a sweet smell.  So there's one way mood could easily come out with a smell -- but the smell you describe sounds worse. Ketones don't smell "bad", but they definitely smell like something. 

Then there's something as simple as not brushing her teeth, I suppose; or not drinking enough fluids so that what's in her mouth is not getting flushed as much by our own natural salivary secretions. Beyond that, I 'd be really guessing.  Clearly your question was something more along the lines of the first paragraph.  I wish there was a simple answer so we could get on with using it! But any explanation for bipolar disorder is going to have to connect directly into the story on depression, which as you can see from that essay linked above is a very complicated story indeed. So while I'd be delighted were we to stumble on a simple explanation with a simple answer, I doubt that's what we'll find.  And I'm usually rather optimistic, so this may mean something!  Thanks for your question. 

Dr. Phelps


Published September, 2005