C-reactive protein as a possible indicator of PTSD prognosis and comorbid anhedonia.

Posttraumatic stress disorder (PTSD) is often chronic, which is costly to the individual and society. Easy-to-measure prognostic indicators can help to ensure that those with the greatest symptoms receive treatment. Inflammatory biomarkers may precede and predict depression chronicity and worsening, as well as PTSD. Yet, it is unknown if inflammatory biomarkers predict changes in symptoms among those who have already developed PTSD. Among 82 US military veterans (82 % male) diagnosed with PTSD, we measured C-reactive protein (CRP) and conducted clinical diagnostic interviews assessing PTSD and major depression at two visits, an average of five years apart. Cross-lagged models revealed that CRP at Time 1 was positively associated with PTSD symptom severity (p = 0.017), depression diagnosis (p < 0.001), depressive symptom count (p=.001), and anhedonia (p < 0.001) but not low mood (p = 0.183) at Time 2, covarying for baseline levels of these outcomes as autoregressive effects and for potential confounds. Results suggest that elevated CRP may be a risk factor for more chronic and severe PTSD symptoms, perhaps with comorbid anhedonic depression. Further exploration of CRP as a prognostic indicator of PTSD is warranted.