Inflammation in depression confirmed in three independent studies
AUGUST 28, 2008
Three new studies on depression and inflammation by the Stress, Psychiatry and Immunology Section, headed by Dr. Pariante. Inflammatory cells in the blood have the primary task to fight infections in the body; however, we now know that these cells also have the ability to regulate behaviour.
In the first study, conducted in collaboration with the SLAM Affective Disorder Unit, Dr. Livia Carvalho has found that patients with depression have increased levels in the blood of a substance that is produced by the inflammatory cells and greatly affect brain function, the so called interleukin-6. This substance is normally elevated in situations of danger and stress. Additionally, in these patients the inflammatory cells do not respond to an antidepressant when it is added to the blood in a laboratory experiment. This may be the first step into the development of a “blood test” to understand which patient may respond to which antidepressant, akin to the tests of “sensitivity” used for choosing the right antibiotic.
In the second study, conducted in collaboration with Psychological Medicine at King’s College Hospital, Miss Sarah Bull has found that people who have a specific form of the gene for interleukin-6 (the blood substance described above) predicts the risk of developing depression during a treatment that activates inflammation for therapeutic purposes, that is, during treatment with interferon-alpha for chronic infections of the liver. This study identifies this “inflammation” gene as a potentially important factor in predicting the risk of developing depression.
Finally, in the third study, conducted in collaboration with the China Medical University Hospital, in Taichung, Taiwan, Dr. Kuan-Pin Su has found, in a controlled study, that treatment with omega-3 fatty acids (“fish oil”), a natural product that reduces inflammation, has antidepressant action in depression during pregnancy. Considering the ongoing debate regarding the use of drugs for depression during pregnancy, this study proposes that fish oil is a safe treatment, and at the same time highlights once again the important role of inflammation in depression.
Taken together, these lines of evidence indicate that increased inflammation participates in the development of depression, and that in turn, reducing inflammation has therapeutic antidepressant action
Carvalho LA, Juruena MF, Papadopoulos AS, Poon L, Kerwin R, Cleare AJ et al (2008). Clomipramine In Vitro Reduces Glucocorticoid Receptor Function in Healthy Subjects but not in Patients with Major Depression. Neuropsychopharmacology .
Bull SJ, Huezo-Diaz P, Binder EB, Cubells JF, Ranjith G, Maddock C et al (2008). Functional polymorphisms in the interleukin-6 and serotonin transporter genes, and depression and fatigue induced by interferon-alpha and ribavirin treatment. Mol Psychiatry.
Su KP, Huang SY, Chiu TH, Huang KC, Huang CL, Chang HC et al (2008). Omega-3 fatty acids for major depressive disorder during pregnancy: results from a randomized, double-blind, placebo-controlled trial. J Clin Psychiatry 69: 644-651.