Cytokines & Depression
While depressive disorders are thought to be subserved by neuroendocrine and neurotransmitter variations, the illness is also associated with immune alterations, as well as elevations of cytokine production. In view of the possibility that variations of cytokine levels/production may related to stressor events (and chronicity), as well as specific neurovegetative features associated with depression (e.g., reduced eating, reduced sleep) we have been evaluating the relationship between cytokine production and levels in subtypes of depression, including dysthymia (chronic, low grade depression) and major depression, as well as patients exhibiting typical or atypical features (the latter display increased sleep, increased eating).
In collaboration with several associates (Zul Merali, Arun Ravindran), we also evaluate the effectiveness of various forms of therapy (drug, cognitive) in dysthymia and major depression and relate these to endocrine and cytokine alterations, stressor perception and coping styles. Our research confirmed the efficacy of pharmacotherapy in treatment of dysthymia. Moreover, the work indicated that quality of life, coping styles and stress perception differentiated genuine treatment responders (to either drug treatment or cognitive therapy) from placebo responders (placebo responders show reduced stress, but not improvements in quality of life and perceived uplifting events). Our view of the illness has been that dysthymia may involve excessive exposure or perception of stressful events, coupled with the use of inappropriate coping strategies. We further suggest that this leads to prolonged hypothalamic-pituitary-adrenal stimulation culminating in inappropriate inhibitory feedback.