APPROACHES TO TREATMENT DECISIONS FOR PSYCHIATRIC COMORBIDITY IN THE MANAGEMENT OF THE CHRONIC PAIN PATIENT

CHRONIC PAIN

0025-7125/99 $8.00

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APPROACHES TO TREATMENT DECISIONS FOR PSYCHIATRIC COMORBIDITY IN THE MANAGEMENT OF THE CHRONIC PAIN PATIENT David A. Fishbain, MD, FAPA

Cornorbidity is defined as ”any distinct clinical entity that has existed or that may occur during a patient’s clinical course who has the index disease under study.”18It has become clear that the presence of comorbid disease can dramatically affect the treatment of the index disease. Specifically the presence of comorbid disease can often complicate, interfere with, or make the treatment of the index disease more difficult, making the prognosis worse.61In addition, the presence of comorbid disease, because of its impact on the treatment of the index disease, can lead to spurious medical outcome data, especially if the comorbid disease is not classified, not analyzed, and its effect not controlled for.61For these reasons, there has been significant psychiatric research interest on comorbidity, on different types of comorbidities present within psychiatric patients, the effects of comorbid disease on the index disease, and the effects of comorbid disease on treatment outcome. Psychiatric comorbidities can be divided into five large categories. The first category is comorbidities between psychiatric disorders on Axis This work was partially supported by National Institute on Disability and Rehabilitation Research grant H133A00032.

From the Departments of Psychiatry, Neurological Surgery, and Anesthesiology, University of Miami School of Medicine; and Comprehensive Pain and Rehabilitation Center, South Shore Hospital, Miami Beach, Florida

MEDICAL CLINICS OF NORTH AMERICA

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VOLUME 83 * NUMBER 3 MAY 1999

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FISHBAIN

I of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV).’ An example of this category of comorbidity is the presence of major depressive disorder in association with panic disorder. This first category of comorbidity is extremely common in the general population. For example, in a US psychiatric diagnosis lifetime prevalence study,47 it was found that of individuals with a lifetime psychiatric disorder, 79% had a comorbidity associated psychiatric disorder, with three or more disorders being common. The second major category of psychiatric comorbidity is that of comorbidities between Axis I psychiatric disorders and Axis I1 (personality disorders).’ An example of this type of comorbidity is the presence of depression (Axis I) in association with antisocial personality disorder (Axis 11). This second major category of psychiatric comorbidity is also extremely common within psychiatric population^.^^ In addition, there is significant evidence that the presence of a comorbid disorder on Axis I1 influences the symptoms and clinical course of the index Axis I disorder as well as the choice of therapy and treatment The third major category of psychiatric comorbidity is that between Axis I psychoactive substance use disorder diagnoses and other psychiatric disorders on Axis I. An example of this type of comorbidity is the presence of alcohol dependence in association with major depression. This category of comorbidity is extremely common within patients with psychiatric problems. Reports indicate that for those with any mental disorder, the lifetime prevalence for addictive disorders is about 29% (22% for alcohol, 15% other drugs).76The fourth major category of psychiatric comorbidity is that of comorbidities within psychoactive drug use disorders only. An example of this type of comorbidity is the presence on Axis I of cocaine dependence in association with alcohol dependence. This category of comorbidity is also extremely common within the psychiatric p ~ p u l a t i o n . ~ ~ The final category of psychiatric comorbidity is that between all psychiatric disorders (both on Axis I and Axis 11) and between any nonpsychiatric disorder or physical illness (e.g., hypertension). It has become clear that this category of psychiatric comorbidity may be the most commonly encountered by the practicing physician because it appears that most forms of physical illness are associated with depression. Depression has been identified in 2% to 45% of patients with physical illness depending on the method used.” In addition, researchgo indicates that patients with physical illness are at greater risk for developing psychiatric illness. The lifetime prevalence rates for any psychiatric condition are far greater for patients with one or more medical conditions than those patients without medical condition^.^^ Finally, psychiatric comorbidity on Axis I in association with medical illness can increase the incidence of sick leave.39 For a number of reasons, significant psychiatric comorbidity in chronic pain patients (CPPs) is expected. CPPs consider themselves to suffer from a physical illness for which physicians cannot seem to develop a curez7;this physical illness is associated with significant impairment and disability that has tremendous impact on CPPs’ livesz7;to

APPROACHES TO TREATMENT DECISIONS FOR PSYCHIATRIC COMORBIDITY

739

control pain, CPPs are often placed on psychoactive substances, which have dependence and addiction potentialz2;and because often no apparent tissue damage can be found to explain the cause of chronic benign nonmalignant pain, physicians frequently attribute CPPs’ pain to underlying psychiatric illness. To address the issue of comorbidity between chronic pain and psychiatric disorders, research in this area is reviewed. This research is reviewed according to the major categories of psychiatric comorbidities described earlier. COMORBlDlTlES BETWEEN CHRONIC PAIN AND AXIS I PSYCHIATRIC DISORDERS

Although limited, comorbidities between chronic pain and Axis I psychiatric disorders are the most exhaustively studied and documented major category of psychiatric comorbidity in CPPs. Data from various research studies for prevalence percentages with CPPs for Axis I disorders are summarized in Table 1. Table 1 also attempts to answer two questions: (1) Are these comorbid psychiatric disorders more common in CPPs than in the general population, and (2) how reliable is the research data (i.e., are there discrepancies between authors)? Table 1 indicates that the affective disorders (depression) group is the most commonly found group of comorbid disorders. For example, some authors have reported a prevalence rate for depression approaching In a review, Fishbain et alZ6concluded that depression is more commonly found in CPPs than the general population and that the depression seen in CPPs is a consequence of chronic pain and is not involved in the cause of chronic pain. As noted in Table 1, there are discrepancies between authors on reported prevalence rates of the various types of affective disorders. These discrepancies relate to three problems: (1) differences in pain center CPP selection criteria,30(2) lack of operationally specified instructions for determining organic factors to the depression as required by the DSM-111-R and DSM-IV35and ( 3 ) the effect of pain on mood. The effect of pain on mood may be an extremely important issue because this may be the reason for the high prevalence of comorbid affective disorders in CPPs. The second most common group of Axis I psychiatric comorbidities to be found in CPPs is that of psychoactive substance use-related disorders (see Table 1). Fishbain et a134 reviewed this research area and concluded that the prevalence percentages for the diagnoses of drug abuse, dependence, or addiction in CPPs were in the range of 3.2% to 18.9%. A significant percentage of CPP, 6.41% to 12.5%, was reported to abuse illicit drugs (marijuana and cocaine).34There was, however, little evidence that addictive behaviors were common.34As indicated in Table 1, it is probable that the prevalence of substance-related disorders is greater in CPPs than the general population but that there are discrepancies between research reports. The third most common group of Axis I psychiatric comorbidities

Table 1. PERCENTAGES OF COMORBIDLY ASSOCIATED DSM, AXIS I DISORDERS WITH CHRONIC PAIN ALONG WITH REFERENCES Prevalence Within Chronic Pain Patients

(%I

Psychiatric Disorder

Affective disorders (depression) Major depression Dysthymia Adjustment disorder with depressed mood All forms affective disorders Psychoactive substance-related disorders Current alcohol abuse/ dependence Current drug dependence (opioids, barbiturates, sedatives, cannabinoids) Current illicit drug abuse (cocaine, cannabinoids, speed) Total current alcohol and other drug dependence Somatoform disorders Somatization disorder Conversion disorder Psychogenic pain/pain disorder Hypochondriasis Anxiety disorders Panic disorder Panic disorder with agoraphobia Posttraumatic stress disorder Adjustment disorder with anxious mood Obsessive-compulsive disorder Phobic disorder Total anxiety disorder Other diagnoses Psychotic disorders including schizophrenia Marital problem Psychological factors affecting medical condition Adjustment disorder with work inhibition Intermittent explosive disorder No diagnosis on Axis I

More Common Than General Population?

Discrepancies Between Authors

Probably ? ?

Yes

Yes17

Yes

Probably

Yes

Probably

Yes

Probably

Yes

Probably

Yes

Probably Probably Probably

Yes Yes Yes

No

No

Probably Probably

Yes Yes

Probably

Yes

Probably

Yes

No

Yes

Probably Probably

Yes Yes

?

Yes

Probably Probably

Yes Yes

5-13jo, 71

Probably

Yes

9.930

?

?

3-5.230,68

Less

No

1.5-54.5j" 72 0-43.330 28.3)O

14.9-23.4"

55

? ?

APPROACHES TO TREATMENT DECISIONS FOR PSYCHIATRIC COMORBIDITY

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to be found in CPPs is that of the somatoform disorders (see Table 1).Here, both conversion disorder and psychogenic / pain disorder are reported to have high prevalence rates (see Table 1). There are major discrepancies, however, between authors on the prevalences of these two disorders. These discrepancies have been commented on previouslyS.l5 and relate to reliability problems with DSM-I11 criteria for both of these diagnoses.21, Both of these diagnoses contain or have contained criteria that require the examiner to make a value judgment about a symptom. As a result of these problems, the DSM criteria for psychogenic pain were changed in the DSM-111-R and further changed in the DSM-IV.21It is therefore likely that the data for the prevalences of these disorders are unreliable. The fourth most common group of Axis I psychiatric comorbidities to be found in CPPs is that of anxiety disorders (see Table 1). The reported high prevalence of anxiety disorders is not surprising because anxiety is the only psychiatric disorder that is commonly associated with any chronic medical condition.82,91 It is also reported that this association develops more quickly than any other association between a psychiatric 91 Although, as demonstrated disorder and a chronic medical condition.82, in Table 1, anxiety is common in CPPs, evidence indicates that these reported prevalences are underestimates. The evidence for this statement comes from studies performed with non-CPPs. K a t ~ has n ~ reported ~ that 81% of panic disorder patients had pain as a presenting complaint. G i l ~ r i s has t ~ ~ reported that in general practices low back pain patients are more likely to have a diagnosis of anxiety than non-low back pain patients. Finally, CPPs, when compared with non-CPPs, are more likely to demonstrate avoidance of particular situations (e.g., injections and minor surgery, hospitals, sight of blood, thoughts of injury and illness [blood or injury phobia], being watched or stared at, and speaking or acting to an audience [social p h ~ b i a ] )It. ~is therefore likely that anxiety syndromes are comorbidly associated with chronic pain at a greater frequency than reported. The fifth most common group of Axis I psychiatric comorbidities to be found in CPPs is that of the other diagnoses group (see Table 1).Here, two diagnoses are important: psychotic disorders, including schizophrenia, and psychological factors affecting medical condition. In reference to psychotic disorders, schizophrenia, delusional disorder, and bipolar affective disorder are not overrepresented compared with the general population and are probably ~nderrepresented.~~ In patients with atypical facial pain, 10.3% have been reported to suffer from either schizophrenic or delusional disorders,” and Carrocini et allo reported a 15% prevalence of psychotic disorders in reflex sympathetic dystrophy patients. It is likely that these discrepancies are related to CPP treatment selection criteria and self-selection. It is also possible that some select pain problems, such as reflex sympathetic dystrophy, may not share the same distribution of DSM disorders as other pain problems, such as low back pain. In reference to the diagnosis of psychological factors affecting physical condition, there are major discrepancies between authors. These

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FISHBAIN

differences are likely related to reliability problems with the criteria for this diagnosis.21These problems are the same as those pointed out for the somatoform disorders. COMORBlDlTlES BETWEEN CHRONIC PAIN AND AXIS II PSYCHIATRIC DISORDERS

Comorbidities between chronic pain and Axis I1 psychiatric disorders are the second best studied group (Table 2). Here, studies indicate that the prevalence of personality disorders in CPPs may range from 31% to 59Y0.~~ These rates may be high because of a number of problems pointed out by FishbainzoThis area requires further study. In reference to the types of personality disorders cornorbidly associated with chronic pain, no clear consistent trends are evident. Authors are in conflict as to which personality disorders are most commonly found in CPPs. COMORBlDlTlES BETWEEN AXIS I PSYCHIATRIC DISORDERS ASSOCIATED WITH CHRONIC PAIN

Comorbidities between Axis I psychiatric disorders associated with chronic pain have been ignored by chronic pain researchers. Only one study has reported on this issue.30 Fishbain et aPOreported on the distribution of total number of Axis I diagnoses for men and women. For men, the distribution was as follows: no diagnosis, 5.7%; one diagno-

Table 2. PERCENTAGES OF COMORBIDLY ASSOCIATED DSM, AXIS II DISORDERS WITH CHRONIC PAIN ALONG WITH REFERENCES Prevalence Within Chronic Pain Patients Psychiatric Disorder

Personality disorders Paranoid Schizoid Compulsive Histrionic Dependent Narcissistic Borderline Passive-aggressive Avoidant Self-defeating Mixed Schizotypal Antisocia1 Total of samples

("/.I

More Common Than General Population? ? ? ? ?

? ? ? ? ? ? ? ? ?

Probably

Discrepancies Between Authors

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

APPROACHES TO TREATMENT DECISIONS FOR PSYCHIATRIC COMORBIDITY

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sis, 35.9%; two diagnoses, 33.3%; three diagnoses, 16.0%; and three or more diagnoses, 9.0%. For women, the distribution was as follows: no diagnosis, 4.7%; one diagnosis, 33.9%; two diagnoses, 34.6%; three diagnoses, 18.9%; and three or more diagnoses, 7.9%. Therefore, 58.4% of the men and 61.4% of the women had more than one diagnosis on Axis I. Therefore, a significant number of CPPs should have Axis I diagnoses comorbidly associated with other Axis I diagnoses. The specifics of this comorbidity category have not yet been investigated in CPPs. This category may significantly affect CPP treatment outcome. COMORBlDlTlES BETWEEN AXIS I AND AXIS II PSYCHIATRIC DISORDERS ASSOCIATED WITH CHRONIC PAIN

There is no information on comorbidities between Axis I and Axis I1 psychiatric disorders associated with chronic pain. Fishbain et a130 have reported that in their sample of 283 CPPs, 62.3% of the men and 55.1% of the women were assigned an Axis I1 diagnosis. In this sample, 94.3% of the men and 95.3% of the women had one or more diagnoses on Axis I. Therefore, it is highly likely that this type of comorbidity is commonly present within CPPs. The exact details of this comorbidity have yet to be determined. COMORBlDlTlES BETWEEN AXIS I PSYCHOACTIVE DRUG USE DISORDERS AND OTHER AXIS I DISORDERS ASSOCIATED WITH CHRONIC PAIN

There has only been one study25of comorbidities between Axis I psychoactive drug use disorders and other Axis I disorders associated with chronic pain. Fishbain et a125analyzed three groups of CPPs for the prevalence of Axis I diagnoses other than psychoactive drug use disorder diagnoses. These three groups were (1)CPPs with a current alcohol use disorder diagnosis, (2) CPPs with a current drug use disorder diagnosis, and (3) groups 1 and 2 groups combined. These groups were compared to CPPs without any of the aforementioned alcohol or drug use diagnoses. Some DSM affective and personality disorder diagnoses were found to be more frequently associated with all the psychoactive drug use disorder groups versus the remaining CPPs. These results indicate that, as has been described for psychiatric populations, this category of comorbidity is to be found in C P P S . ~ ~ COMORBlDlTlES BETWEEN VARIOUS AXIS I PSYCHOACTIVE DRUG USE DISORDERS ASSOCIATED WITH CHRONIC PAIN

There is little information on comorbidities between various Axis I psychoactive drug use disorders associated with chronic pain. There is,

744

FISHBAIN

however, some indirect evidence that points to the presence of this category of comorbidity in CPPs. Fishbain et alZ4compared the following two groups of CPPs for the prevalence of Axis I psychoactive drug use disorders: a group positive on urine toxicology giving correct information on current illicit drug use according to urine toxicology and a group positive on urine toxicology giving incorrect information on current illicit drug use according to urine toxicology. The results indicated that the false information group was more likely to have a history of illicit drug use disorders in the past. These indirect data indicate that subgroups of CPPs may suffer from multiple comorbid psychoactive drug use disorders. OTHER COMORBIDITY PROBLEMS COMMONLY FOUND ASSOCIATED WITH CHRONIC PAIN

There are a number of other comorbidly associated problems commonly found in CPPs. These problems do not fall within the DSM nomenclature and may or may not be psychiatric in nature. These problems, however, dramatically affect the difficulties involved in the care and treatment of the CPP, and treatment plans for CPPs cannot be developed without taking these problems into account. These problems are pain behaviors, significantly impaired functional status out of proportion to the identified organic problem causing the pain, sleep difficulties, nonorganic physical findings, and somatization. CPPs are characterized by displaying pain behavior^.^, 12, 74 Pain behaviors are “any and all outputs of the patient that a reasonable observer would characterize as suggesting pain, such as (but not limited to) posture, facial expression, verbalizing, lying down, taking medications, seeking medical assistance and receiving compensation.”s1 Pain behaviors can often be elicited during physical examination and correlate with physical examination findings, number of operations, and longer pain h i ~ t o r i e sIn .~~ addition, pain behaviors correlate with perceived severity of pain and extent of functional impairment^.^^ As pain improves, pain behavior dim in is he^.^^, 74 CPPs often demonstrate discrepancies between reported pain level and functional status versus the physician’s perception of what the CPP should be able to do functionally according to the physical findings. This perception discrepancy is attributable to a number of complex problemsZ2:CPPs perceive their pain as a disability that limits their functional status; the pathology model does not predict back pain, making the reliability and validity of this model questionable; and for a proportion of CPPs, nonverbal expression may be discordant with selfreports. The resultant discordance in perceptions between CPPs and their physicians often leads to labeling CPPs as having psychiatric problems. CPPs often demonstrate nonorganic physical findings. These are eight physical examination signs found in CPPs with lower back pain or neck pain. Earlier in the twentieth century, these signs were identified

APPROACHES TO TREATMENT DECISIONS FOR PSYCHIATRIC COMORBIDIlY

745

as predominantly nonorganic.2s,29, 31 Waddell et alS5have demonstrated that a large percentage of patients with chronic lower back pain demonstrate these eight nonorganic physical signs. These signs appear to be predictive of treatment 86 and Waddell et alS6 have suggested that their presence or absence should be used as a basis for surgical decisions. Most importantly, these signs correlate with a greater degree of pain behavior and therefore a more difficult treatment pr0blem.8~In addition, the presence of one or more of these signs makes the patient a candidate for the psychiatric diagnosis of conversion disorder, a somatoform disorder. The vast majority of CPPs complain of severe sleep disturbance." 65, 92 These sleep problems are usually a result of pain.65Although CPPs can usually fall asleep, they are frequently aroused by pain65;thus, sleep is fragmented and of poor The medical literature commonly uses the term somatization.sOYet there is little agreement about its definitions0L i p o ~ s kdefines i ~ ~ somatization as "a tendency to experience and communicate somatic distress and symptoms which are unaccounted for by pathological findings, and to attribute them to physical illness, and to seek medical help for them. It is usually assumed that this tendency becomes manifested in response to psychosocial stress brought about by life events and situations personally stressful to the individual." Somatization does not represent a specific DSM medical psychiatric or medical diagnosis and does not necessarily imply that a psychiatric disorder must be present.80 Because somatization is not a specific diagnosis, it does not have operational criteria by which it can be established. Thus, in CPPs, somatization has been studied by questionnaires. These studies indicate that a high percentage of CPPs demonstrate elevated hypochondriasis score@ and somatization scores7sas measured by the Illness Behavior Questionnaire and the Modified Somatic Perceptions Questionnaire. In addition, when patients with various types of chronic pain are compared with appropriate controls on somatization measures, CPPs are frequently demonstrated to have greater somatization scores. Higher scores have been 93 migraines,62noncardiac demonstrated for CPPs with orofacial chest painIRchronic low back painT7and fibromyalgia.' Finally, somatization scores appear to be predictive for treatment outcome in CPPs with temporomandibular disorderss4 and low back pain.14 According to the aforementioned literature, somatization may be a significant problem in CPPs, and CPPs with this problem may be at risk for poor treatment outcome. Ford36has pointed to similarities in somatization between the DSM-IV2 somatoform disorders (hypochondriases, conversion disorder, somatization disorder, pain disorder, undifferentiated somatoform disorder, somatoform disorder not otherwise specified, body dysmorphic disorder), factitious disorders, and malingering. He has grouped these disorders under the term somatizing disorders.36The prevalence of some of these disorders in CPPs is presented in Tables 1 and 3. Malingering is not defined as a mental disorder but is an act, and it is therefore not an official psychiatric illness.2 It is defined as the conscious and deliberate

746

FISHBAIN

Table 3. PERCENTAGES OF COMORBIDLY ASSOCIATED OTHER SOMATIZATION DISORDERS WITH CHRONIC PAIN ALONG WITH REFERENCES

Psychiatric Disorder

Factitious disorders Malingering (not classified as a psychiatric disorder)

Prevalence Within Chronic Pain Patients (%)

More Common Than General Population?

Discrepancies Between Authors

0.14-2.032,71 0-2223

Probably ?

Yes Yes

production, simulation, or exaggeration of a symptom for some conscious gain, such as obtaining disability payments or avoiding military service.2There are few studies of malingering, and as such it is difficult to determine the prevalence of this condition. Fishbain et alZ3have reviewed this literature as it relates to pain. Fishbain et alZ3found that the range for reports of malingering in CPPs is between 0 and 22%. This finding is in stark contrast to the report of the Institute of Medicine on Pain and Disability, which could not find any studies relating to malingering and pain and concluded that malingering was rare in the chronic pain setting.4l Fishbain et al,23however, cautioned that the presented figures are likely to be incorrect because of the poor quality of the reviewed studies. The above-mentioned other comorbidities are important considerations in making treatment decisions for the CPP. As such, these other comorbidities are used in some of the subsequent tables and algorithms.

IMPORTANCE OF PSYCHIATRIC COMORBlDlTlES TO CHRONIC PAIN Research indicates that psychiatric comorbidities often have a negative impact on chronic pain and functional status. For example, anxiety can change pain threshold and tolerance50 and increase pain ratings.I3 Comorbidity depressed CPPs demonstrate more automatic hyperactivity (muscle tension)88and may be more sensitive to acute pain stimuli.49 In addition, evidence indicates that depression may magnify medical symptoms.44Depression57and phobias54have also been reported to be associated with role impairment and loss of function. For example, individuals with subsyndrome depressive symptoms of major depression report significantly more impairment in 8 of 10 functional domains than individuals without subsyndrome depressive symptoms." Comorbidities between Axis I psychiatric disorders in association with chronic pain can also have a significant impact on chronic pain treatment and outcome. This impact is the result of each of the comorbid Axis I disorders causing more severe symptoms of the other Axis I disorders3 Because a high percentage of CPPs have more than one

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747

comorbid Axis I disorder, they are at risk for the aforementioned problem. Comorbidities in CPPs between Axis I and Axis I1 psychiatric disorders can also affect the treatment of CPPs. For example, atypical depression (the type seen in pain facilities) is more frequently associated with personality disorders, making this type of depression more difficult to treat.I7This type of comorbidity could therefore also affect chronic pain treatment. USING PSYCHIATRIC COMORBlDlTlES IN THE MANAGEMENT OF CHRONIC PAIN Table 6 summarizes the various categories of comorbidities found in CPPs. These categories of comorbidities are used here in a suggested approach to treatment decisions for the CPP. Thus, information about the presence of psychiatric comorbidities should be used by the generalist in decisions about the management of the CPP. In fact, the author believes that outside of other medical issues, the aforementioned categories of psychiatric comorbidities should be the most important consideration in treatment decisions. To aid the clinician in using the various categories of psychiatric comorbidities, three algorithms have been developed (Figs. 1-3). These algorithms are based on certain basic principles that are discussed subsequently. The algorithm in Figure 1 is based on whether the CPP has any category of psychiatric comorbidity or has an other category of comorbidity. If the answer to either of these questions is no (see Fig. l), the generalist may proceed to chronic pain treatment as in the third algorithm (see Fig. 3). If the generalist is uncertain about the presence of any comorbidity, a psychiatric consultation should be sought with a psychiatrist familiar with chronic pain or who is a pain specialist. CPPs who demonstrate psychiatric comorbidities 111, IV, V, VI, or I with substance abuse or dependence should be treated in collaboration with a psychiatric colleague. This is because these comorbidities relate to either psychoactive drug misuse or to a number of concurrent psychiatric comorbidities. As pointed out earlier, the presence of more than one psychiatric comorbidity or a psychoactive drug misuse comorbidity makes that CPP a difficult treatment problem. Treatment failure for a CPP with a category I1 comorbidity is also an indication for concurrent psychiatric treatment (see Fig. 1).The algorithm in Figure 1 also indicates that treatment failure at 6 months both by the generalist and by the generalist/ psychiatrist is an indication for consideration for treatment at a pain facility. Inclusion and exclusion criteria for this decision are outlined in Table 4. Use of the other category of comorbidity as inclusion criteria is extensive in this table. Treatment failure at a pain facility raises the issue of possible narcotic treatment. It is pointed out in Figure 1 that the presence or absence of psychiatric comorbidities should be used in making this decision. It

Prodeed to Algorithm Ill

1

I \

According to these comorbidities, does CPP fulfill criteria for referral to a pain facility (Refer to Table IV)

psychiatric colleague who is pain swcialist

I

dependence?

Algorithm I

I

Generalist may attempt to treat this type of CPP

1

Proceed to Algorithm II

psychiatric disorders in the context of chronic

treatment at a pain facility (Table IV)

to a pain facility for treatment

fulfills inclusion criteria outlined in Table V. except for CPPs with comorbiditiesV. VI or I (with substance abuse or dependence)

Figure 1. Algorithm I: Does CPP have psychiatric comorbidities I , II, 111, IV, V, or VI?

treatment and attempt rehabilitation

treatment and attempt rehabilitation

Difficulties encountered with treatment

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FISHBAIN

Table 4. INDICATIONS FOR MULTIDISCIPLINARY PAIN CENTER OR OTHER PAIN FACILITY TREATMENT Major inclusion criterion (required for referral) Chronic pain or chronic benign pain >3-6 mo in duration Minor inclusion criteria (one criterion required for referral) Severe pain behavior Presence of nonorganic physical findings Impaired functional status or perceived functional impairment Disability perception Discrepancy in perceptions between the physician and the chronic pain patient on ability to function Drug abuse, dependence, or addiction Significant psychopathology associated with chronic pain Failed back surgery syndrome Chronic pain patient refusing or denied surgery Myofascial pain syndrome and fibromyalgia Diagnosis of somatoform pain disorder (psychogenic pain) Failure of conservative management Failure of one isolated mode of treatment (eg., physical therapy alone) Exclusion criteria (any one criterion precludes referral) Inability to understand and carry out instructions Aggressive or violent behavior Imminently suicidal Unwillingness to participate in a pain center program because this can lead to noncompliance, uncooperativeness, and failure of the behavior modification process Unrealistic expectations of what can be accomplished (seeking an immediate cure) Unstable medical condition (e.g., uncontrollable high blood pressure, congestive heart failure) Dafa from Fishbain DA, Rosomoff HL, Steele-Rosomoff R, et al: Pain treatment facilities referral selection criteria. Clin J Pain 11:156-157, 1995.

is suggested that CPPs with comorbidities V, VI, or I with substance abuse or dependence should not be placed on narcotic treatment. Inclusion and exclusion criteria for CPP narcotic treatment are outlined in Table 5. The algorithm in Figure 2 is based on what type of psychiatric comorbidity is present within a category I comorbidity. Here the three main types of psychiatric comorbidities (depression, anxiety, somatoform disorders) other than psychoactive substance use disorders are presented. Failure at treatment of each of these types of comorbidities is an indication for referral to a psychiatric colleague who is familiar with the treatment of psychiatric pathology in the context of chronic pain. According to the algorithm in Figure 2, treatment failure in concurrent psychiatric treatment is an indication for pain treatment at a pain facility because invariably these treatment failures are related to poor pain control and its consequences.26 The algorithm in Figure 3 presents a psychopharmacologic approach to the treatment of the pain component in chronic pain. The algorithm in Figure 2 presented an approach to the psychiatric pathology component in chronic pain. In Figure 3, the generalist is first asked to establish if the CPP is having nociceptive, muscle, or neuropathic pain. Psycho-

APPROACHES TO TREATMENT DECISIONS FOR PSYCHIATRIC COMORBIDITY

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Table 5. POSSIBLE INCLUSION AND EXCLUSION CRITERIA FOR POTENTIAL CHRONIC NARCOTIC TREATMENT

Inclusion criteria (#1 or #2 and #3 required) 1. CPPs who are depressed and suicidal because of their pain, especially if they have failed antidepressant treatment 2. CPPs whose quality of life is extremely poor and intolerable because of pain 3. Failure of all forms of pain treatment, including blocks and pain facility treatment that includes detoxification Exclusion criteria (any one of 1-5 required) 1. A history of alcohol abuse or dependence 2. Any history of illicit drug use (e.g., cannabinoids, cocaine) 3. Any history of unauthorized escalation of therapeutic drugs, such as benzodiazepines 4. Any history of other addictive behaviors69 5. Heavy smokers with inability to quit CPPs = Chronic pain patients. Data from Fishbain DA: Opinion on chronic opioid analgesic therapy. Pain Med Network 12:163, 1997.

pharmacologic treatment is dictated by this division because these types of pains have been shown to respond to different pharmacologic agentsz2Nociceptive pain responds best to nonsteroidal anti-inflammatory drugs; muscle pain to muscle relaxants; and neuropathic pain to antidepressants, anticonvulsants, and local anesthetics. This concept is incorporated into the algorithm. It should also be noted that the following conceptsz2are also integrated into this algorithm: (1)Antidepressants have a significant antinociceptive effect independent of their antidepressant effect; (2) there is no relationship between antidepressant serum levels and the antinociceptive effect; (3) target symptoms for antidepressant treatment with CPPs should be sleep (other comorbidity) and pain; (4) antidepressant doses should be the maximum tolerated by CPPs addressing these two target symptoms; and (5) some antidepressants, Text continued on page 756 Table 6. COMORBlDlTlES FOUND WITHIN CHRONIC PAIN PATIENTS Psychiatric Comorbidities I Chronic pain and psychiatric disorders on Axis I I1 Chronic pain and psychiatric disorders on Axis I1 I11 Within CPPs and between psychiatric disorders on Axis I IV Within CPPs and between psychiatric disorders on Axis I and Axis I1 V Within CPPs and between Axis I psychoactive drug use disorders and other Axis I disorders VI Within CPPs and between various Axis I psychoactive drug use disorders Nonpsychiatric ComorbiditieMther Comorbidities Pain behavior Decreased functional status out of proportion to identified organic problem causing pain Sleep problem Nonorganic physical findings Somatization CPPs

=

Chronic pain patients.

\

Treat with doses of antidepressant required to treat depression and with antidepressant appropriate to the type of depression

t

depressive syndrome major depression 01 dysthymia

YES

f

No depression treatment required. Go to Alaorithm 111.

Algorithm II

I

improvement in

1

I

Treat with required doses of appropriate antianxiety agent

comorbidity I an anxiety syndrome?

t

L

PEl

somatoform disorder?

1

Is comorbidity I a

Begin chrodc pain treatment as in Algorithm 111

CPPs' depression, anxiety disorder or somatoform disorder is unlikely to respond because of the chronic pain component

NO

treatment and attempt rehabilitation

/

Figure 2. Algorithm II: Is comorbidity I a depressive syndrome?

Continue treatment and attempt rehabilitation

t

YES

lmpro ement in Depression anxiety or somatoform disorders

1

Refer to concurrent treatment with psychiatric colleague who is a pain specialist

Trial with NSAID

1

&,

(Nociceptive)?

Trial of other muscle relaxants

t

Failure 7

t

dose tolerated

Trial of Lioresal titrated to max

spasms (muscle pain) ?

+

Algorithm Ill

1 Use desipramine at maximum tolerated dose

improved?

Is the patient's chronic pain

\/

Use arnitriptyline, doxepin or clomipramine at whatever dose necessary to restore sleeo

I

pejfj+,

D es CPP have a sleep disturbance associated with chronic pain?

+q

(neurologic) or dysestheticsensation (dysestheticquality) ( Neuropathic pain)?

Continue treatment and attempt ihabilitation

I

t

imDroved?

Is chronic Dain

t

derivative

I

NO

I

Refer for cnnc rrent evaluation and treatment by a psychiatric colleague who is a pain specialist

Figure 3. Algorithm 111: What type and quality of pain does CPP have?

treatment

Continue with regimen and monitor pain behavior

YES

t

Is chronic pain improved?

+Add anticonvulsant e.g. clonazepam

2TF

Treatment Continue

Consider referral to a pain facility for

1

Failure pain facility treatment

fl

t

Consider chronic narcotic treatment if fulfills inclusion criteria outlined in Table V except for CPPs with comorbiditiesV, VI or I (with substance dependence)

t

Continue treatment and attempt rehabilitation

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such as amitriptyline, doxepin, clomipramine, and desipramine, have been demonstrated consistently to have an antinociceptive effect versus some others, such as the selective serotonin reuptake inhibitors, which have not. As indicated in the algorithm in Figure 3, failure of antidepressant treatment for neuropathic pain is an indicator for the addition of an anticonvulsant followed by a local anesthetic drug. Failure of this regimen should again raise the possibility of concurrent psychiatric treatment, possible pain facility referral, and possible narcotic treatment. CONCLUSIONS

Psychiatric comorbidities and other comorbidities are extremely important in the proper management of chronic pain. As such, decisions about chronic pain treatment should be partly based on an understanding of the psychiatric comorbidities associated with chronic pain. ACKNOWLEDGMENT The author thanks Ellen Markowitz for manuscript typing.

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