When I started this blog way back in June, I was worried about a lack of material. Paleo psychiatry? There's no data, I thought, or nothing solid enough worth writing about. Not a single controlled trial of any diet intervention (other than omega 3 pills or vitamins) that I'm aware of. It's no type II diabetes, where diet interventions are studied to the extreme. I figured I could throw out the basic info and write up a bit on the omega 3 fatty acid trials of depression and bipolar disorders, maybe speculate a bit on eating disorders, and then I'd be scraping for more. I'd likely move on to paleo psychology and talk about how preserving sociopathy in the gene pool keeps our species tough and ready to fight. Well. Here we are. Ninety-two blog entries later. New biology stuff arrives in my email and in the comments on a daily basis. My more immediate plans include wrapping up the Alzheimer's series with a post on some of the infectious cause papers - though Alzheimer's stuff comes out every hour so I doubt it will ever be wrapped up, digging into the thyroid, and more about mental illness and obesity/metabolic syndrome (huge topic), not to mention diving into sleep. In between that the papers come out, and keep coming. I'm like a kid in front of a fire hose.
Today another paper from the Journal of Affective Disorders. "Associaton of seropositivity for influenza and coronaviruses with history of mood disorders and suicide attempts." I like the Journal of Affective Disorders. It's edgy without being desperate. The Anna Sui of the psychiatry world.
The paper starts out with some depressing statistics - mood disorders are expected to be the second leading cause of global disease burden by 2030 (medical students - psychiatry is a promising field), and nearly 21 million adult Americans have a mood disorder. A mood disorder (such as major depression or bipolar disorder) is (obviously) a major risk factor for attempting suicide.
Guess when the "busy season" is for psychiatry. Not the summer! That's true. Most everyone is happy in the summer. But when is everyone really depressed? Wrong! It's not during the winter holidays (northern hemisphere winter, that is). We actually get the most emergency phone calls in September, October, the end of February, and March, when the amount of light changes exponentially day by day. Fall is bad, but spring is much, much worse, and that's not something I would have predicted before residency. Beware the Ides of March.
Springtime is also the busy time for the flu. And seasonal suicide peaks overlap or closely follow seasonal peaks in epidemic influenza and upper respiratory viruses. (These peaks also happen during the yearly nadir of vitamin D levels, don't you know?). I've certainly noticed that my patients with depressive and other mood disorders tend to be down for a few weeks after recovering from a cold or flu. Apparently I'm not the only one who has noticed - back in 1892 Tuke wrote up a series of "post-influenza mania and depression" cases admitted to a London hospital.
So what did the researchers do? They took 257 subjects, mostly female, including 39 healthy controls. They were already involved in a study on environmental influences on exacerbation of mood disorders and suicidal behaviors. (It is perhaps not well known that all scientific research is in fact done on some thousand-odd college students and ex-hippies who are amenable to being recruited for study after study from the same medical center). These participants met criteria for major depressive disorder or bipolar disorder (or were controls), and answered questionnaires about their suicide history. Then they gave some blood, and the blood was examined for seropositivity for previous infection with several viruses, including influenza.
And guess what? People with previous flu and coronavirus (a common cold virus) infection had a much higher chance of having major depressive disorder. We're talking p=0.004 and p< 0.0001 for influenza A, B, and coronoavirus, so highly significant. Previous infection with influenza B was significantly associated with a previous suicide attempt as well (p=0.001), with an odds ratio of 2.53. Influenza B also seemed to increase the risk of having psychotic symptoms in mood disorder patients. Coronavirus and influenza A didn't seem to increase the risk of suicide or psychosis.
Wow. Okay. You mean these "mental" diseases might be biological?!? Immune response to the flu and other viruses involves cell-mediated immunity and a flurry of cytokine activation. Turns out those same things are active in the biological cascade of depression. The same old interleukins and TNF-alpha are involved in everything. Cytokines tend to make tryptophan into kyrunetic rather into serotonin, and that is not so good for the mood, and even worse for suicide. Influenza and coronoviruses are also possibly active in the brain itself, but the evidence is a little sketchy.
I have to admit, during medical school in residency I never got my flu vaccine. I didn't remember ever getting the flu before, and I washed my hands plenty, so hey... once I had kids, I got my yearly shot. According to a presentation I attended back in April, 10-20% of adults will never get the flu. They are lucky, or especially immune. The other 80% of you - here's something to think about. And ratchet up that vitamin D. Can't hurt.
0 comments:
Post a Comment