36 Pain and Affective Disorders
The Massachusetts General Hospital Handbook of Pain Management
Pain and Affective Disorders
Daniel M. Rockers and Scott M. Fishman
Happiness is not being pained in body or troubled in mind.
—Thomas Jefferson (1743–1826)
I. Mood disorders
1. Major depression
3. Bipolar disorder
II. Anxiety disorders
1. Generalized anxiety disorder
2. Panic disorders
3. Post-traumatic stress disorder
The majority of patients in chronic pain have comorbid psychiatric conditions, ranging from mild (anxiety, adjustment, depression) to severe (delusional, psychotic). The chronology of these conditions often makes it difficult to determine whether the pain caused the psychiatric diagnosis, the psychiatric condition caused the pain, or they occur simultaneously. Depression and anxiety are known to enhance perceptions of pain and may be a predominating component of some pain syndromes. Some psychiatric conditions may even manifest as pain or pain-like symptoms. For example, it has been suggested that complex regional pain syndrome is a conversion-like disorder (Ochoa, and Verdugo 1995).
Many psychiatric conditions are caused by or are accompanied by neurochemical abnormalities. These abnormalities may significantly affect the pain medications prescribed and may affect the pain condition in a significant manner. For example, serotonin is considered an important factor in pain as well as mood states. The dramatic overlap of the drugs used to treat both pain and psychiatric disorders suggests that common mechanisms may be at work in each. Because of this, comprehensive pain management requires an understanding of basic principles of psychiatric diagnoses and how they might affect or be affected by pain.
I. MOOD DISORDERS
Mood disorders are often split into two general categories: unipolar and bipolar disorders. Unipolar disorders include major depression and dysthymia (a less severe variant of depression). Bipolar disorders include bipolar I (combination of manic and depressive episodes), bipolar II (combination of depressive and hypomanic episodes), and cyclothymia (a less severe variant of bipolar disorder).
1. Major depression
Depression is the psychological issue most frequently associated with chronic pain. Major depression is found in 8% to 50% of patients with chronic pain, and dysthymia may be seen in greater than 75% of patients with chronic pain. At particular risk for major depression are women, those of lower socioeconomic status, those separated or divorced, those with a family history of depression, those with negative stressful events, those not having a confidant, and those living in urban areas.
For a clinical diagnosis of depression, the following are required: (a) at least 2 weeks of either depressed mood or anhedonia (loss of interest) in nearly all activities, and (b) four of the following additional symptoms: changes in appetite or weight, sleep difficulties, changes in psychomotor activity, decreased energy, feelings of worthlessness or guilt, difficulty thinking, and recurrent thoughts of death or suicide. In addition, these symptoms must significantly impair an individual’s social, occupational, or other functioning.
It is important to distinguish between depression and other naturally occurring mood states, such as bereavement or normal states of sadness. The use of rapid assessment instruments such as the Beck Depression Inventory or the Hamilton Rating Scale for Depression (HAM-D) augments and documents interview impressions but does not replace them. Use collateral information as well; patients themselves may be poor historians or not recognize when these feelings began to emerge—remember that some of the symptoms include an inability to think, concentrate, or make decisions and may impact the ability to recall. Keep in mind that depression may manifest in a number of various symptom constellations; for example, children may experience depression more in terms of somatic complaints, social withdrawal, or irritability.
Suicide risk is greatest for those depressed patients with psychotic functioning, a history of past attempts, family history of completed suicides, or concurrent substance abuse. The astute practitioner is aware when a depressed patient exhibits a loss of impulse control or when cognitive faculties are compromised to the point of poor judgment. When patients are judged to be a significant suicide risk, take standard precautions such as having them sign a written contract to not harm themselves, identify appropriate social support, and help elucidate reasons to continue living. For patients who cannot be left alone, secure family or a friend’s assistance, or consider hospitalization. For those in imminent danger of harm to themselves or others, most state laws mandate that any treating clinician, including a pain specialist, must take action to ensure safety as well as formal psychiatric evaluation.
Course and treatment
Symptoms may develop over days or weeks; there may be a prodromal phase characterized by slight anxiety or light depressive symptoms. Duration is variable. An untreated depression typically lasts 6 months or longer, regardless of age at onset. Although the majority of patients experience remission, a significant minority (20% to 30%) continue to have symptoms over a period of 1 to 2 years. In addition, two out of three experience a recurrence.
There are many contemporary models of depression, including cognitive, learned helplessness, reinforcement, biogenic amine, neurophysiologic, and final common pathway. Cognitive or psychological models suggest cognitive and behavioral treatments, whereas biologic models tend to suggest pharmacologic treatments. Beck’s characterization of a cognitive triad of depression is that the self is seen in a negative light, the current situation is viewed negatively, and the future is viewed negatively. These cognitions are very common in a chronic tormenting condition such as pain. Seligman’s learned helplessness model is that one’s responses to the environment are ineffective—that they will not bring relief.
Many patients with chronic pain experience depressive hopelessness about their pain condition, and it is easy to experience negative thoughts or feelings of helplessness when faced with ceaseless pain. The pain seems to (and frequently does) control life. The experience is one of a tormenting, unremitting taskmaster. Psychosocial treatment of unipolar depression consists of behavioral therapy, cognitive-behavioral therapy, or interpersonal therapy. These treatments, discussed in Chapter 15, can result in significant reduction in depressive symptoms and maintain their effect after treatment is terminated. The goal in these treatments is to restructure negative beliefs and enable the patient to experience some sense of self-efficacy in life. Acceptance of the pain condition is often difficult, but it allows movement out of the current depressive state.
Pharmacologic treatment of depression is typically accomplished through antidepressant drugs (see Chapter 11) such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs) (which have recently gained in favor because of their safety and reported efficacy), and a third class called atypical antidepressants. There are documented analgesic effects of TCAs that are independent of the antidepressant effects. To date, the SSRIs have not consistently demonstrated such effects.
When an individual experiences less severe depressive symptoms that persist for a long time (2 years), they may be diagnosed with dysthymia. Many of the symptoms are the same as for depression, but individuals typically experience fewer vegetative symptoms (i.e., sleep difficulties, weight change, psychomotor agitation, or psychomotor retardation). Dysthymia is a risk factor for major depression—75% of those diagnosed with dysthymia go on to develop major depression within 5 years. Women are two to three times more likely to develop dysthymia than men. Lifetime prevalence is approximately 6%.
3. Bipolar disorder
Bipolar disorder is characterized by a cyclic mood fluctuation between mania and depression. These fluctuations may be predominately manic, with depressive episodes (bipolar I) or depressive episodes may predominate, with hypomanic episodes also occurring (bipolar II). Risk factors for bipolar I include higher socioeconomic status, being separated or divorced, and having a family history of bipolar I. The first episode in men is likely to be manic, whereas the first episode in women is likely to be depressive.
A manic episode is a discrete period in which a number of somatic and cognitive responses are accelerated. Patients in a manic phase experience an elevated, expansive, or irritable mood. They may have an expanded or grandiose sense of themselves or have flights of ideas or racing thoughts. Vegetative or behavioral symptoms include a decreased need for sleep, talkativeness, an increase in goal-directed activity, and excessive involvement in pleasurable activities such as unrestrained buying sprees or sexual indiscretions. Judgment is often impaired. At its extreme, the mania degenerates into psychotic behavior. A depressive episode meets criteria for major depression, as described earlier. The same caveats for depression diagnosis apply to bipolar disorders, and collateral information is a very important aspect, as patients may be poor historians when manic or depressed.
Suicide attempts are made by 25% of those with bipolar disorder and 10% to 15% complete suicide—it is a genuine and important concern. There may be abuse or violent behavior when an individual is in a manic episode, as well. Safety may be a paramount concern in fulminant cases. Many drugs common to pain management, such as corticosteroids or antidepressants, can induce mania and must be used with caution.
Course and treatment
Mean age of onset for a manic phase is 20, although some patients begin younger and some have begun as late as 50. Sleep deprivation or abrupt changes in sleep/wake cycles can initiate manic or depressive episodes. The course is chronic; 90% of those with one manic episode go on to have future episodes. The frequency and intensity of episodes tend to decrease as an individual ages. It is important to recognize that manic episodes and depressive episodes can “color” perceptions of pain, so a patient’s pain may look like a different animal when the bipolar condition is treated.
A leading conceptualization of bipolar disorder is that it is a disorder of biologic regulation that is activated or maintained by stressful or negative life events. Thus, treatment should be both pharmacologic and psychosocial. As a dysregulation of biology, the primary treatment is pharmacologic. Lithium is the classic agent for treating bipolar disorder, although recently many other agents such as anticonvulsants have gained popularity. Maximize pharmacologic treatments by using medications that target both the pain and the bipolar condition, if possible. For example, membrane stabilizers used for neuropathic pain are often mood stabilizers as well (see Chapter 11).
Psychosocial treatments include psychoeducation, individual psychotherapy, and family therapy. Psychosocial treatments are especially important because bipolar disorder can have devastating effects on an individual’s life as well as on family. For example, it is not unusual for an individual to acquire thousands of dollars of debt during a manic phase. Individual psychotherapy helps patients understand their condition better, decrease relapses, and remain adherent to pharmacologic therapies.
Chronic pain patients with comorbid bipolar disorder need appropriate education about both bipolar disorder and chronic pain. The challenge is to maintain the course through speeding highs and dark immobilizing lows. This includes maintenance of medication for both disorders and the clear overarching knowledge that the current phase will eventually change.
II. ANXIETY DISORDERS
In the spectrum of comorbid pain and affective disorders, anxiety ranks high. For some, the anxiety is a manifestation of the response to the pain, and for others it is a separate entity that can amplify and distort pain and pain perception. There are many disorders with the common characteristic of anxiety. This section includes generalized anxiety disorder (GAD), panic disorders, and post-traumatic stress disorder (PTSD).
1. Generalized anxiety disorder
GAD is considered the “basic” anxiety disorder. It is characterized by excessive anxiety and worry lasting for at least 6 months, often about routine things. The amount of worry and anxiety is out of proportion to the likelihood of the negative consequences occurring, and the individual has much difficulty controlling the worry. Diagnosis requires at least three of the following: restlessness, easy fatigability, difficulty concentrating, irritability, muscle tension, sleep disturbance.
Current models of GAD advocate that there exists a biologic and psychological vulnerability. That, combined with the feeling that situations are outside one’s control, leads to neurobiologic changes and excessive self-evaluation. This further fuels the feelings of external control, and the cycle intensifies.
Lifetime prevalence estimates are around 5%. Be aware that some cultures tend to display anxiety in more cognitive symptoms, while others have more somatic symptoms. It is uncommon for GAD to begin after age 20. The course is chronic but tends to worsen in times of stress.
Studies of psychological treatments have shown that active treatments are superior to nondirective treatments. The most common successful therapies involve some variant of relaxation therapy combined with cognitive therapy. The task is to bring the stress under the individual’s control, which is often done through cognitive restructuring and exposure through graded practice. Several studies have shown cognitive–behavioral therapy superior to benzodiazepine treatment.
Although clinicians typically perceive GAD as a “worry” or an otherwise cognitive disorder, many of the symptom manifestations are somatic. As noted, there may be associated muscle tension, trembling, twitching, muscle aches, soreness, nausea, diarrhea, sweating, headaches, or irritable bowel symptoms. It is possible for an individual to present in the pain clinic with undiagnosed GAD.
2. Panic disorders
Panic attacks are periods of intense fear or discomfort that develop rapidly and reaches a peak within 10 minutes. They are commonly characterized by a number of discrete cognitive or somatic symptoms, such as the following: palpitations, sweating, trembling or shaking, shortness of breath or sensations of smothering, feelings of choking, chest pain, nausea, dizziness, derealization (the surrounding environment seems unreal), depersonalization (the individual feels unreal, but the environment seems real), fear of losing control or “going crazy,” fear of dying, paresthesias (numbness or tingling), chills, or sweats.
Panic disorder and its variants (e.g., with agoraphobia, without agoraphobia) are the actual diagnoses that involve panic attacks. To meet criteria for panic disorder, the symptoms should not be attributable to the use of substances such as stimulants or caffeine. For diagnosis, there must be at least one panic attack (at least four of the preceding symptoms, manifesting and peaking within 10 minutes) followed by at least 1 month of persistent concern of having another attack. Patients with this diagnosis usually have other intermittent feelings of anxiety, and they may have a sense of being demoralized. This is because (a) the attacks are often crippling, (b) they may appear to arise of their own accord, and (c) the individual begins to feel little self-efficacy and is unable to get things done.
(i) Course and treatment
Patients usually first experience panic disorder in their teens or early twenties. There may be prodromal symptoms of mild anxiety, or the attack may simply erupt. There is often no way for a patient to predict when the next attack will occur, which leads to anticipatory anxiety. A current leading model of anxiety disorders suggests that an individual has a biologic predisposition, and when placed in a stressful situation involving loss of control, anxiety and panic occur. Lifetime prevalence figures indicate that panic disorder with or without agoraphobia occurs in about 3.5% of the population.
Between 50% and 65% of individuals with panic disorder also have a diagnosis of major depression. Some individuals may treat their anticipatory anxiety, panic, or depression with other substances such as alcohol, thereby developing a comorbid substance abuse disorder. The physician should be careful not to unwittingly treat panic symptoms with analgesics.
Treatment involves educating the patient about the nature of anxiety and panic, coping skills acquisition, and in vivo exposure. Patients are often taught relaxation and diaphragmatic breathing techniques to help combat physiologic symptoms. The course fluctuates and some symptoms may persist even after treatment. The main goals are to decrease subjective anxiety while improving objective function and the ability to travel.
It is not uncommon to see diagnosable panic disorder in the pain patient. Chronic pain often shares with panic disorder a component of apparent uncontrollability. Many patients begin to experience panic or extreme anxiety about impending pain. As the pain begins to emerge, they fear it as an entity in itself; the pain is often experienced as a tormenting aspect with its own volition. Patients with pain should also understand that stimulants may exacerbate both pain and anxiety and so should be utilized with caution.
3. Post-traumatic stress disorder
When subjected to extreme traumatic stressors, individuals may develop PTSD, a characteristic disorder that involves ongoing residual anxiety. Diagnostic criteria require that the traumatic stressor be extreme, and the individual’s response involves intense fear, helplessness, or horror. Examples of extreme traumas include involvement in hostage situations, terrorist attacks, torture, war combat, physical or sexual abuse, and automobile accidents. The residual anxiety manifests in re-experiencing events related to the stressor, avoidance of reminders of events, and persistent increased autonomic system arousal. The hyperarousal may show up in sleep disturbance, irritability, hypervigilance, or an exaggerated startle response. Avoidance is accomplished by avoiding thoughts of, or feelings about, the event. It may also show up as amnesia for a part of the event. Diagnosed individuals may also have a restricted range of affect and feel detached from others.
Associated with PTSD is an increase in somatic complaints such as pain, or increased autonomic nervous system arousal. On the pain service, it is not unusual to have war veterans and assault or abuse victims as patients. Lifetime prevalence of PTSD is estimated at 8% of the adult population. About half of those diagnosed with PTSD experience complete recovery in 3 months.
Accepted and empirically supported treatment for PTSD is exposure therapy plus anxiety management techniques. Exposure therapy usually consists of imagery as well as exposure-type treatments (in vivo), whereas anxiety management techniques include relaxation, breathing retraining, trauma education, guided selfdialogue, cognitive restructuring, and anger management. Pharmacologic therapies may involve treatments with antidepressants as well as other psychiatric drugs.
As there is an affective component to all pain, there is a common comorbidity of affective disorders and chronic pain. In addition, a chronic stressor such as pain taxes the affective regions of the psyche, which can manifest as an affective disorder. Conversely, an affective disorder can present as a pain disorder. Regardless of primacy, attempts to identify and treat affective disorders should occur simultaneously with identification and treatment of somatic pain disorders.
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