Abstract
Centers for Disease Control criteria for chronic fatigue syndrome (CFS) specifically recognize that patients can have both CFS and depression. The clinician's challenge is to judge for each individual patient whether the complaint of fatigue is primarily depression, physical illness, such as CFS, or a combination of both.
This review differentiates CFS and fibromyalgia, discussed as “chronic fatigue syndrome and related immune deficiency syndromes” (CFIDS), from depression in terms of physical signs, symptoms, biological parameters, brain imaging, immunology, and treatment. The review focuses on practical applications of research findings with a further focus on future ability to show clear biologic separation and specific treatment.
When depressive symptoms exist with those of CFS, accurate differentiation can usually be accomplished by focusing on diagnostic criteria. Presence of multiple physical signs and symptoms of CFIDS may be of great value. In terms of laboratory testing, a single helpful test may be measuring the plasma cortisol, which is usually high in depression and low in CFS. Future research should focus on the combination of plasma cortisol with an index of serotonin function, which is high in CFIDS and low in depression. Additional research should focus on neuroimaging and immune differentiation. Combination of multiple tests should result in a significant and clinically useful separation between CFIDS and major depressive disorder (MDD).
In treating patients with significant depression or MDD with CFIDS, one should think of the noradrenergic approach using bupropion or low-dose tricyclic antidepressants in combination with a selective serotonin reuptake inhibitor, especially sertraline, to aid improvement of global, pain, and immunologic parameters. Alternatively, serotonin norepinephrine reuptake inhibitors (venlafaxine and duloxetine) should be considered. Future treatment research should focus on larger placebo-controlled, double-blind trials of these and other antidepressants as well as the evaluation of psychostimulants, electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS).