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Some depression might have roots in immune-generated inflammation

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some depression might stem from inflammation caused by the immune systemNEW YORK—The immune system works hard to keep us well physically, but might it also be partly to blame for some mental illnesses?

"The immune system may play a significant role in the development of depression," Andrew Miller, a professor of psychiatry and behavioral sciences at Emory University School of Medicine, said Tuesday at a symposium on neuroscience and immunology at the New York Academy of Sciences. Evidence for this link has been mounting in recent years, and he described this research, which falls in the jauntily named field of psychoneuroimmunology, one of the most exciting recent developments in psychiatry.

Research has shown that depressed or stressed-out people tend to be more susceptible to medical ailments, such as infectious diseases and perhaps even cancer. But the correlation might also work in the opposite direction, Miller explained. People who are critically ill have about five to 10 times higher rates of depression, and that might not just be due to battling their illness, he noted. It could be stemming from underlying inflammation—a common bodily response to illness or injury.

Studies have shown that people with depression or bipolar disorder, both those who had a physical illness and those who were medically healthy, had higher levels of inflammation. And as the depression faded, so, too, did the evidence of inflammation. Similarly, a 2009 study showed that mice that with chronic inflammation showed depressive symptoms, but blocking a key inflammatory enzyme alleviated the downer behavior in the mice.

The big discovery has been that depressed patients who have proved most resistant to traditional treatments (such as therapy or selective serotonin re-uptake inhibitor drugs) seem to have particularly high rates of inflammation. And in studies from the last few years, inhibiting inflammatory cytokines (signaling cells found in both the immune and nervous systems) seems to help alleviate depressive symptoms. Miller said that these results suggest that "cytokines might have an effect on fundamental dopamine synthesis," an important chemical process that, if thrown out of whack, can have big impacts on mood, energy and motivation.

If this association holds, keeping inflammatory cytokines in check could also help treat conditions beyond classic depression, such as cancer-related fatigue or even chronic fatigue syndrome, Miller noted. And because much of the inflammation in question seems to be coming from outside of the brain—the periphery, as the neuroscientists like to call it—new depression-targeting drugs might not even have to cross the blood-brain barrier to have palliative effects.

Image courtesy of iStockphoto/Qwasyx

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  1. 1. Andira 4:23 pm 10/28/2010

    A lovely breakthrough. Considering my own history I have suspected something like this for about thirty years. So, the current antidepressant drugs treat the symptoms, not the cause. How obvious! Congratulations to the scientists involved.

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  2. 2. WellnessJess 6:19 pm 10/28/2010

    Yes congratulations to the people involved. Their names were D.D. Palmer and B.J. Palmer, founder and developer of Chiropractic who discovered this in 1895. This is not new information, just something the public has refused to believe for years.

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  3. 3. Julieta 8:25 am 10/29/2010

    I first wondered about this when I started to notice that after taking an anti-inflammatory for period pain or hormonal headaches (naproxen sodium in particular), my chronic depression (not just PMS) temporarily abated. (This is usually not immediate, it might be the next day.)
    Now I sometimes take an anti-inflammatory just to get some respite from depression.
    It would be great to hear from someone who knows of a safe way to get this effect on a long-term basis.
    I don’t want to take something so strong too often as I worry about the effects on my liver and stomach.
    I am trying to have more ginger and turmeric in my diet as they are apparently natural anti-inflammatories but so far don’t notice any benefit.
    Traditional anti-depressants (SSRIs) have not worked for me, just give me anxiety, insomnia, a facial tic, and other side effects.
    As an aside, I also have sticky blood (APAS – anti-phospholipid antibody syndrome,but not Lupus), early onset osteoarthritis in my finger joints (Heberden’s nodes) and PCOS. I mention all that because I suspect it reflect the inflammation in my body and may be relevant to the depression.
    Thank God this inflammation-depression link is now more prominently on the research radar. Let’s hope for more breakthroughs.

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  4. 4. Freddd 11:39 pm 01/2/2013

    Having a cause in common can be a link. Methylcobalamin deficiency can casue inflammation and depression. Adenosylcobalamin (Carmen Wheatley’s Large Gorilla in the Room – Adenosylcobalamin … Inflammation…) deficiency can cause inflammation and deprtession. L-methylfolate deficiency (can be CAUSED by folic acid and veggies, paradoxical folate deficiency and methyl-trap) can casue massive sudden onset inflamation, asthma, allergies, MCS ) and has alread been proven effectove for depression. And the 4th member of the Deadlock Quartet, a lack of l-carnitine fumarate, can also cause inflammation and you guessed it, depression. The 4 of these together can casue over 400 symptoms of every description in body and CNS including impaired tissue formation, massive mood and personality changes and major unstoppable inflammation.

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