Increased inflammation predicts a 9-year change in the diagnostic status of major depressive disorder.
Zainal, New Hampshire and Newman, New Hampshire (2021). Krause, J. M., Krause, J. A., and Krause, J. J. Increases in inflammation predict nine-year changes in the diagnostic status of major depressive disorder. Journal of Abnormal Psychology. Advance online publication. https://doi.org/10.1037/abn0000716
Commentary
This study was designed to test whether increased inflammatory activity at time 1 (T1) predicts intra-individual 9-year change in MDD diagnosis.
Community-dwelling adults (n = 945) participated in the Midlife Development in the United States (MIDUS) study, and T1 and time 2 (T2) MDD status was assessed using the Composite International Diagnostic Interview-Short Form, and inflammatory activity at T1 markers at T1 were measured.
Latent change score modeling was performed.
Higher T1IL-6, CRP, and fibrinogen levels of inflammatory activity predicted the onset/recurrence of T1-T2 of MDD in persons.
This effect occurred more strongly among women (vs. men; d = .149 vs. .042), younger (vs. older) adults (d = .137 vs. .119), and those with more (vs. less) chronic health conditions.
We hypothesized that the impact of increased T1 inflammatory activity on future changes in MDD status would be greater in subgroups more vulnerable to increased stress exposure, a finding consistent with extended cytokine theory.
Cognitive behavioral therapy or pharmacological approaches to reduce markers of inflammatory activity may prevent the onset/recurrence of MDD. General Scientific Summary: Elevated levels of C-reactive protein (CRP), fibrinogen, and interleukin-6 (IL-6) were stronger predictors of change in diagnostic status for major depressive disorder (MDD) over a 9-year period in younger people, women but not men, and lower than in older people. (vs. high) income, and those with high (vs. low) frequency of childhood trauma and number of chronic conditions.
Consistent with the extended cytokine theory, the findings postulated that markers of inflammatory activity would predict future changes in MDD status, especially in populations vulnerable to high, chronic, and prolonged exposure to environmental stressors.
Continued efforts to empirically test the extended cytokine theory of depression may improve the depiction of patterns of health disparities and facilitate effective measures to prevent the onset or recurrence of MDD.
