Fibromyalgia: Psychiatric drugs target CNS-linked symptoms
Repeated pain signals in the periphery may sensitize spinal cord neurons, resulting in amplified and prolonged signals traveling to the brain
CASE CONTINUED: Central pain sensitization
As you elicit more details about Ms. D’s mood, she continues to focus on her physical symptoms. She states that some days she wishes to die because her pain gets so bad, but she denies any plan or intent to harm herself. She worries that her symptoms will worsen and that she will become completely disabled.
Her primary physician attempted to relieve Ms. D’s pain with multiple trials of nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclobenzaprine. She says she gained no benefit from the NSAIDs and discontinued the muscle relaxant because it made her too sleepy. Fibromyalgia affects 3.5% of women and 0.5% of men.5 It runs in families with histories of fibromyalgia and major mood and anxiety disorders, suggesting genetic links.6 Defects in genes controlling serotonin and norepinephrine have been implicated.7-9
Fibromyalgia patients show lower levels of serotonin, norepinephrine, and dopamine metabolites in cerebrospinal fluid (CSF), compared with controls.10 These neurotransmitters may inhibit descending pain pathways in the CNS, and low levels in the brain and spinal cord may inhibit CNS regulation of pain impulses from the periphery.11
Although many patients describe muscle pain, evidence suggests central pain augmentation rather than an abnormality of muscle or connective tissue.12 Some studies have found evidence of “windup,” in which second-order neurons in the spinal cord become sensitized by repeated signals from first-order neurons in the periphery, resulting in amplified and prolonged pain signals traveling to the brain.13
Levels of substance P—a primary transmitter of pain impulses—are significantly higher in CSF of fibromyalgia patients compared with controls.14 This finding, in addition to low levels of serotonin and norepinephrine, indicates that pain signals are ascending unchecked to be processed by the brain.
- Twice as much pressure was required before controls rated their pain at a level similar to that of fibromyalgia patients.
- When controls and fibromyalgia patients reported similar pain, a very high degree of overlap was seen in brain areas responsible for pain processing. This indicates that fibromyalgia patients and controls were experiencing the pain they reported in the same way.15
Treating the whole patient
As a clinician who specializes in fibromyalgia, I counteract my patients’ and my own frustration with this condition by structuring office visits, determining realistic treatment goals, and treating all symptoms as part of a common syndrome rather than individual illnesses.
Structure office visits. Before every visit, have patients rate each symptom domain and write their top 2 or 3 concerns for that day (Click here for a sample form). Focusing on the patient’s most troublesome symptoms can help both of you feel greater satisfaction with treatment.
Educate patients. Ask them to discuss their beliefs about fibromyalgia; many know others with this condition or have researched diagnosis and treatment. Before developing a treatment plan, explain that their symptoms are chronic and all part of the same syndrome. Describe their pain as a complex phenomenon with possible peripheral and CNS components. Guide them to reputable Web sites and resources (see Related Resources).
Set realistic expectations. Many patients expect to resume an energetic and pain-free life, which usually is not the case with fibromyalgia (Box). Most medications are considered successful if they reduce pain by 30% to 50%, and side effects can be problematic. Discuss side effects before treatment begins to reduce patients’ anxiety and improve compliance in the first weeks.
Cognitive-behavioral therapy (CBT) for fibromyalgia incorporates relaxation techniques, helping patients view symptoms as manageable, reinforcing adaptive coping skills, and teaching them how to monitor thoughts, feelings, and behavior to change the view that they are helpless victims. A modest course of 6 weekly group CBT sessions significantly improved physical functioning in 25% of fibromyalgia patients (n=76) compared with 12% in a standard-care group (n=69), even though patients’ pain severity did not improve.16
