› To achieve optimal outcomes for patients with chronic pain, treat the constellation of symptoms that often accompany it—eg, disordered sleep, depression or anxiety, and/or substance abuse—as well as the pain. A
› Individualize drug therapy for patients with chronic pain (eg, specific comorbidities and symptoms) while considering drug-based factors, including adverse effect profiles and the potential for interaction with other agents. A
› Consider using a tricyclic antidepressant, a serotonergic/noradrenergic antidepressant, gabapentin, or pregabalin for patients who have chronic pain and depression or anxiety. A
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Primary care physicians often have the lead role in caring for patients with chronic pain from a myriad of causes, including arthritis, low back injury, migraine, neuropathic pain, and more.1 To ensure optimal outcomes for such patients, understanding chronic pain syndromes and their negative effect on sleep, mood, and daily functioning is key.
Studies of the interaction of chronic pain, insomnia, and psychiatric disorders are increasing awareness of the way patients with this constellation of comorbidities respond to treatment. What they show is that optimal outcomes are possible only if we treat these co-occurring disorders simultaneously.
Pain affects multiple functions
While pain is thought to originate from a primary dysfunction in the nervous system, the mind and body are involved in the constellation of pain, sleep disturbances, depression, anxiety disorders, and substance abuse/dependence. Patients with chronic pain typically report a higher degree of impairment in all dimensions of quality of life and sleep, and have higher scores on anxiety or depression screens than those without chronic pain.2
Sleep. About two-thirds (65%) of patients with chronic pain and the vast majority (96%) of those with fibromyalgia report sleep disturbances, with difficulty falling asleep, staying asleep, or both.3,4 Sleep deprivation has a hyperalgesic effect, which leads to decreased pain tolerance and greater severity and pain-related disability.5,6 While there does not appear to be a causal link between poor sleep and the onset of new pain symptoms, treatment directed toward improving sleep may help to reduce pain severity.
Depression. In primary care settings, more than 27% of patients with chronic pain meet diagnostic criteria for comorbid depression.7 The relationship between pain and depression is bidirectional, whereby chronic pain predicts the onset of new depressive episodes and depression predicts the onset of chronic pain.8 Having both conditions is associated with greater pain intensity, greater interference with usual activities, and a lower likelihood of responding to treatment.8 That finding highlights the importance of screening for depression in patients who present with somatic complaints, such as fatigue and headache, and in treating both depression and the pain simultaneously.
Anxiety. The relationship between pain and anxiety also appears to be bidirectional. The prevalence of anxiety disorders—including generalized anxiety disorder (GAD), panic disorder, and social phobia—is about twice as high among patients with chronic pain than in the general population.9
In primary care settings, anxiety disorders often are unrecognized and untreated. What’s more, anxiety can cause or exacerbate pain symptoms10; higher prevalence rates for arthritis, migraines, and back pain have been found in patients with a GAD diagnosis than in those without it.9 In older adults, pain conditions such as arthritis and migraines are associated with significantly higher rates of anxiety.11
Substance-related disorders. Substance abuse and dependence are an increasing problem worldwide, especially in developed countries. In North America, according to a 2012 report from the International Narcotics Control Board, approximately one in every 20 deaths of individuals ages 15 to 64 years is related to substance abuse.12 Canada has been found to have the world’s highest per capita consumption of high-potency opioids.13 In the United States, prescription drug abuse has been targeted as a public health epidemic.14 Also of note: Chronic pain affects 24% to 67% of patients with substance use disorders.15
Because of their analgesic effect, opioids often are given to patients with chronic noncancer pain, but substance misuse is common. Patients with a history of substance abuse or dependence are 4 times more likely to receive a prescription for opioids than those without such a history, and often are given higher potency opioids at higher doses.16 What’s more, individuals with chronic pain and a history of substance abuse/dependence generally have poorer outcomes, typically because they require more intensive treatment but rarely get it.17 These findings highlight the need to develop strategies to manage the symptoms of chronic pain in individuals who have a history of substance abuse or dependence—and to prevent addiction in patients without such a history.