Which psychological disorders are sometimes confused with Fibromyalgia? Why?
Functional psychiatric disorders, such as the somatoform disorders, often result in symptoms identical to those of FM. The term functional suggests that the syndrome has no organic basis and is due to purely psychologic factors. It is conceivable that in some patients with FM, the condition originates as a functional disorder and subsequently the objective clinical, sleep, and neurotransmitter abnormalities become manifest as a result of neuro-psycho-immuno-endocrine interrelationships. Thus, while a “functional” psychiatric disorder could in theory precipitate FM in some patients, FM itself is not a functional disorder in that “organic” pathophysiologic mechanisms have been identified as the etiology of symptoms.
Organic psychiatric disorders, such as major depressive disorder (MDD) and anxiety disorder, are present in up to 75% of patients with FM. Furthermore, many patients diagnosed with MDD experience symptoms of sleep disturbance, fatigue, and musculoskeletal pain. Given these overlapping features, it can be difficult (if not impossible) for a clinician to distinguish between FM and MDD at the initial encounter, and in roughly three-fourths of patients with FM, both conditions will be present.
Finally, the anxiety and mild depression often present in FM may be a psychologic response to concerns regarding financial and personal independence in the setting of chronic pain and disability. This association may be present in any chronic pain or debilitating syndrome.