Investigating the relationship between biomarkers of inflammation and treatment-responsiveness in people with depression (with both high- and low- prior treatment-resistance).
There is now a lot of evidence that inflammation plays a role in mood disorders, but the research literature contains substantial inconsistencies, implying that there is a complicated relationship between inflammation and depression. Many studies support the theory that inflammation is a ‘state’ (as opposed to trait) marker in depression and bipolar disorder (in which case, people who have been but are no longer depressed would have similar levels of inflammation to those who have never been depresed), and our previous meta-analysis suggests that increased inflammation in some patients may predict poor response to treatment (see Publications), though the mechanisms for this are unclear at present.
We are aiming to address inconsistency and uncertainty in the existing literature by investigating a possible predictive role of key inflammatory markers in treatment response within various patient-subgroups with affective disorder. These biological and clinical assessments are made before and after a course of naturalistic treatment, as well as in healthy control subjects. The patient-subgroups include bipolar and unipolar, treatment resistant and non-/early-treatment resistant, melancholic and non-melancholic depression, and because the inflammation-depression relationship appears to be complex, in all participants different symptom clusters will be compared to explore associations with different inflammatory profiles. Predominantly, symptoms that map most closely to those of sickness behaviour will be inspected, as these may explain the presence of abnormal cytokine levels. Secondarily, measures of stress and trauma, personality and psychiatric comorbidity will be studied in terms of both inflammation and response, as these variables have been implicated in increased inflammation levels in previous research. A further secondary aim is to investigate any differential effects between those receiving psychological and/or pharmacological therapies.
Data for the high treatment-resistant participants is currently being analysed, and for the low treatment-resistant group is still being collected.