David A. Fishbain

Chronic pain-associated depression: Antecedent or consequence of chronic pain? A review

OBJECTIVE To determine the current status for the association of chronic pain and depression and to review the evidence for whether depression is an antecedent or consequence of chronic pain (CP). DESIGN A computer and manual literature review yielded 191 studies that related to the pain-depression association. These reports were reviewed and sorted into seven categories relating to the topic of this paper. Eighty-three studies were then selected according to inclusion criteria and subjected to a structured review. SETTING Any medical treatment setting including pain treatment as inclusion criteria for selection of studies. PATIENTS Any patients with any type of chronic pain. RESULTS The reviewed studies were consistent in indicating that there is a statistical relationship between chronic pain and depression. For the relationship between pain and depression, there was greater support for the consequence and scar hypotheses than the antecedent hypothesis. CONCLUSIONS Depression is more common in chronic pain patients (CPPs) than in healthy controls as a consequence of the presence of CP. At pain onset, predisposition to depression (the scar hypothesis) may increase the likelihood for the development of depression in some CPPS. Because of difficulties in measuring depression in the presence of CP, the reviewed studies should be interpreted with caution.

Male and female chronic pain patients categorized by DSM-III psychiatric diagnostic criteria

&NA; Two hundred and eighty‐three chronic pain patients, consecutive admissions to the Comprehensive Pain Center of the University of Miami School of Medicine, received an extensive psychiatric evaluation based upon the American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders (DSM‐III) criteria and flowsheets. All patients received the following type of diagnoses: DSM‐III axis I; DSM‐III axis II, and personality type. The distribution of assigned diagnoses for the entire patient sample was reviewed and a statistical comparison between male and female patients was performed with regards to the prevalence of each diagnosis. Anxiety syndromes and depression of various diagnostic types were the most frequently assigned axis I diagnoses with over half the patient sample receiving each of these diagnoses. Males were significantly overrepresented in the axis I diagnoses of intermittent explosive disorders, adjustment disorders with work inhibitions, and alcohol abuse and other drug dependence, while females were significantly overrepresented in disorders of current depression of various diagnostic types and somatization disorders. 58.4% of the patients fulfilled criteria for axis II personality disorder diagnoses. The most frequently personality disorders found in the patient group were dependent (17.4%), passive aggressive (14.9%), and histrionic (11.7%). Males were significantly overrepresented in paranoid and narcissistic disorders while females were overrepresented in histrionic disorder. The most frequent personality types found in the patient group were compulsive (24.5%) and dependent (10.6%). All personality types were similarly distributed between the sexes. The results of the present study were compared to a previous study of DSM‐III diagnoses in chronic pain patients and are discussed in terms of the prevalence of DSM‐III diagnoses in the general population. Questions are raised as to the applicability of certain DSM‐III diagnoses in the chronic pain population.

What percentage of chronic nonmalignant pain patients exposed to chronic opioid analgesic therapy develop abuse/addiction and/or aberrant drug-related behaviors? a structured evidence-based review

DESIGN This is a structured evidence-based review of all available studies on the development of abuse/addiction and aberrant drug-related behaviors (ADRBs) in chronic pain patients (CPPs) with nonmalignant pain on exposure to chronic opioid analgesic therapy (COAT). OBJECTIVES To determine what percentage of CPPs develop abuse/addiction and/or ADRBs on COAT exposure. METHOD Computer and manual literature searches yielded 79 references that addressed this area of study. Twelve of the studies were excluded from detailed review based on exclusion criteria important to this area. Sixty-seven studies were reviewed in detail and sorted according to whether they reported percentages of CPPs developing abuse/addiction or developing ADRBs, or percentages diagnosed with alcohol/illicit drug use as determined by urine toxicology. Study characteristics were abstracted into tabular form, and each report was characterized according to the type of study it represented based on the Agency for Health Care Policy and Research Guidelines. Each study was independently evaluated by two raters according to 12 quality criteria and a quality score calculated. Studies were not utilized in the calculations unless their quality score (utilizing both raters) was greater than 65%. Within each of the above study groupings, the total number of CPPs exposed to opioids on COAT treatment was calculated. Similarly, the total number of CPPs in each grouping demonstrating abuse/addiction, ADRBs, or alcohol/illicit drug use was also calculated. Finally, a percentage for each of these behaviors was calculated in each grouping, utilizing the total number of CPPs exposed to opioids in each grouping. RESULTS All 67 reports had quality scores greater than 65%. For the abuse/addiction grouping there were 24 studies with 2,507 CPPs exposed for a calculated abuse/addiction rate of 3.27%. Within this grouping for those studies that had preselected CPPs for COAT exposure for no previous or current history of abuse/addiction, the percentage of abuse/addiction was calculated at 0.19%. For the ADRB grouping, there were 17 studies with 2,466 CPPs exposed and a calculated ADRB rate of 11.5%. Within this grouping for preselected CPPs (as above), the percentage of ADRBs was calculated at 0.59%. In the urine toxicology grouping, there were five studies (15,442 CPPs exposed). Here, 20.4% of the CPPs had no prescribed opioid in urine and/or a nonprescribed opioid in urine. For five studies (1,965 CPPs exposed), illicit drugs were found in 14.5%. CONCLUSION The results of this evidence-based structured review indicate that COAT exposure will lead to abuse/addiction in a small percentage of CPPs, but a larger percentage will demonstrate ADRBs and illicit drug use. These percentages appear to be much less if CPPs are preselected for the absence of a current or past history of alcohol/illicit drug use or abuse/addiction.

Drug abuse, dependence, and addiction in chronic pain patients

AbstractIt is claimed that a significant percentage of chronic pain patients suffer from drug/alcohol abuse/dependency/addiction. To address this question, 24 articles alluding to chronic pain patient drug/alcohol dependence/addiction were reviewed according to the following criteria: method for drug misuse diagnosis, which drug misuse diagnosis used (abuse, dependence, or addiction), and percentage of patients within each diagnostic category of drug misuse. The result of the review indicated that only seven studies utilized acceptable diagnostic criteria and/or definitions for the drug misuse diagnoses and gave percentages of drug misuse. Within these seven studies, the prevalence percentages for the diagnoses for drug abuse, drug dependence, and drug addiction were in the range of 3.2–18.9%. It is concluded that these diagnoses occur in a significant percentage of chronic pain patients. However, there is little evidence in these studies that addictive behaviors are common within the chronic pain population.

Evidence-based data on pain relief with antidepressants

This structured review addresses the issue of whether antidepressants have an antinociceptive (analgesic) effect for chronic pain independent of their antidepressant effect. In order to answer this question, human acute pain studies, individual placebo-controlled studies for the treatment of specific chronic pain syndromes, and meta-analytic studies were reviewed and placed into table format. Analysis of this evidence led to the following conclusions: The evidence was consistent in indicating that overall antidepressants may have an antinociceptive effect in chronic pain, and that these drugs were effective for neuropathic pain. There was also some evidence that these drugs could be effective for psychogenic or somatoform disorder-associated pain. This evidence also strongly suggested that serotonergic-noradrenergic antidepressants may have a more consistent antinociceptive effect than the serotonergic antidepressants. Finally, this evidence indicated that antidepressants could be effective for pain associated with some specific pain syndromes, such as chronic low back pain, osteoarthritis or rheumatoid arthritis, fibrositis or fibromyalgia, and ulcer healing. Possible reasons for the conflicting results of studies in this area are presented, and problems that could limit the validity of the conclusions of this review are discussed.

Cocaine-Induced Psychosis and Sudden Death in Recreational Cocaine Users

Fatal cocaine intoxication presenting as an excited delirium is described in seven recreational cocaine users. Symptoms began with the acute onset of an intense paranoia, followed by bizarre and violent behavior necessitating forcible restraint. The symptoms were frequently accompanied by unexpected strength and hyperthermia. Fatal respiratory collapse occurred suddenly and without warning, generally within a few minutes to an hour after the victim was restrained. Five of the seven died while in police custody. Blood concentration of cocaine averaged 0.6 mg/L, about ten times lower than that seen in fatal cocaine overdoses. Police, rescue personnel, and emergency room physicians should be aware that excited delirium may be the result of a potentially fatal cocaine intoxication; its appearance should prompt immediate transport of the victim to a medical facility. Continuous monitoring, administration of appropriate cocaine antagonists, and respiratory support will hopefully avert a fatal outcome.

Diabetic peripheral neuropathic pain: clinical and quality-of-life issues.

Diabetic peripheral neuropathy (DPN) is estimated to be present in 50% of people living with diabetes mellitus (DM). Comorbidities of DM, such as macrovascular and microvascular changes, also Interact with DPN and affect its course. In patients with DM, DPN Is the leading cause of foot ulcers, which in turn are a major cause of amputation in the United States. Although most patients with DPN do not have pain, approximately 11% of patients with DPN have chronic, painful symptoms that diminish quality of life, disrupt sleep, and can lead to depression. Despite the number of patients affected by DPN pain, little consensus exists about the pathophysiology, best diagnostic tools, and primary treatment choices. This article reviews the current knowledge about and presents recommendations for diagnostic assessment of DPN pain based on a review of the literature.

Does Nonsurgical Pain Center Treatment of Chronic Pain Return Patients to Work?: A Review and Meta-analysis of the Literature

Evidence in the literature relating to return to work as an outcome variable for nonsurgical treatment for chronic pain was examined. Study selection criteria were as follows: a detailed definition of patient work status, delineation of work status pre-treatment and at follow-up, and documentation of the proportion of patients employed at follow-up. Of 171 studies reviewed, 37 fulfilled these selection criteria. Because the data were objective in nature, they were abstracted by the senior author only. For the coded variables of time to follow-up, proportion of patients working pre-treatment and at follow-up and number of patients, descriptive statistics and correlations were calculated. Change in employment status at follow-up was significant (P < .005) for all groups examined. In addition, comparisons for work outcome between treated patients versus patients rejected due to lack of insurance, and between treated patients versus patients who dropped out of treatment were both significant (P < .001). The mean difference in employment at follow-up for treated patients versus those not treated was approximately 50%. The proportion of patients working increased from 20% to 54% post chronic pain nonsurgical treatment. Correlation analyses did not find a significant trend in percent employed with time to follow-up. These results indicate that (1) chronic pain nonsurgical treatment does return patients to work; (2) increased rates of return to work are due to treatment, and (3) benefits of treatment are not temporary.

Chronic pain disability exaggeration/malingering and submaximal effort research

OBJECTIVE This is the first review of chronic pain (CP) malingering/disease simulation research. The purpose of this review was to determine the prevalence of malingering within CP patients (CPPs), whether evidence exists that malingering can be detected within CPPs, and to suggest some avenues of research for this topic. DESIGN A computer and manual literature search produced 328 references related to malingering, disease simulation, dissimulation, symptom magnification syndrome, and submaximal effort. Of these, 68 related to one of these topics and to pain. The references were reviewed in detail, sorted into 12 topic areas, and placed into tabular form. These 12 topic areas addressed the following: existence of malingering within the CP setting; dissimulation, identification simulated (faked) facial expressions of pain; identification of malingering by questionnaire; identification of malingered sensory impairment; identification of malingered loss of hand grip strength; identification of submaximal effort by isometric strength testing; identification of submaximal or malingered effort by isokinetic strength testing; identification of submaximal or malingered effort by the method of coefficient of variation; self-deception; symptom magnification syndrome; and miscellaneous malingering identification studies. Each report, in each topic area, was rated for scientific quality according to guidelines developed by the Agency for Health Care, Policy and Research (AHCPR) for rating the level of evidence presented in the reviewed study. The AHCPR guidelines were then used to rate the strength and consistency of the research evidence in each topic area based on the type of evidence the reports represented. All review conclusions were based on the results of these ratings. SETTING Any medical setting reporting on either malingering or disease simulation, or dissimulation, or submaximal effort and pain. PATIENTS Normal volunteers, CPPs, or any group asked to produce a submaximal or malingered effort or a malingered test profile. RESULTS The reviewed studies indicated that malingering and dissimulation do occur within the CP setting. Malingering may be present in 1.25-10.4% of CPPs. However, because of poor study quality, these prevalence percentages are not reliable. The study evidence also indicated that malingering cannot be reliably identified by facial expression testing, questionnaire, sensory testing, or clinical examination. There was no acceptable scientific information on symptom magnification syndrome. Hand grip testing using the Jamar dynamometer and other types of isometric strength testing did not reliably discriminate between a submaximal/malingering effort and a maximal/best effort. However, isokinetic strength testing appeared to have potential for discriminating between maximal and submaximal effort and between best and malingered efforts. Repetitive testing with the coefficient of variation was not a reliable method for discriminating a real/best effort from a malingered effort. CONCLUSIONS Current data on the prevalence of malingering within CPPs is not consistent, and no conclusions can be drawn from these data. As yet, there is no reliable method for detecting malingering within CPPs, although isokinetic testing shows promise. Claims by professionals that such a determination can be made should be viewed with caution.

Do Opioids Induce Hyperalgesia in Humans? An Evidence-Based Structured Review

UNLABELLED DESIGN/OBJECTIVES: Consistent rodent evidence indicates that opioid exposure will decrease the rodents pain threshold (ptr). This is termed opioids-induced hyperalgesia (OIH). Currently, the consistency of the evidence for the occurrence of OIH in humans is unclear. This is a structured evidence-based review for all levels of evidence (all studies and case reports) on OIH in humans in order to determine the consistency of this evidence. METHODS Computer and manual literature searches yielded 504 OIH references (human and animal). Of these, 48 remained after application of inclusion/exclusion criteria. These references addressed 10 hypotheses that the OIH literature has utilized to test for the possibility of OIH in humans. These are the following: opioid addicts maintained on opioids will have decreased ptr and/or tolerance; detoxifying opioid addicts from opioids will increase their ptr and/or tolerance; stopping, decreasing, or rotating to a different opioid or detoxifying from an opioid will improve pain and/or allodynia; chronic pain patients(CPPs) placed on opioids will develop decreased ptr and/or tolerance; CPPs on opioids will have decreased ptr and/or tolerance vs CPPs not on opioids; opioid infusion in normal volunteers or CPPs will decrease ptr and/or tolerance; former opioid addicts exposed to opioids will demonstrate a decrease in ptr and/or tolerance; opioid infusion in normal volunteers will increase secondary hyperalgesia as measured by allodynia or hyperalgesia; perioperative opioids will increase postoperative pain and/or opioid requirements; and placement on opioids postsurgery leads to progressive increased intake (acute tolerance). Each report was characterized by the type of study it represented according to the Agency for Health Care Policy and Research (AHCPR) guidelines and independently rated by two raters according to 14 quality criteria with a quality score calculated. For studies under each hypothesis, an average quality score and the percentage of studies supporting the hypothesis was calculated. Finally, for studies under each hypothesis, utilizing AHCPR criteria, a consistency rating was derived based on the percentage score of studies supporting the hypothesis. RESULTS Two studies had quality scores below 65% and were not utilized. Overall, the strongest evidence (consistent, A) came from opioid infusion studies in normal volunteers as measured by secondary hyperalgesia. This evidence was supported by inconsistent evidence (C) from: studies addressing opioid infusions in normal volunteers or CPPs for decreasing ptr and/or tolerance; and studies addressing increases in postop opioid requirements or pain if peri-opioids were utilized. For the other seven hypotheses, there were too few studies to draw a conclusion or the evidence for the hypothesis were case reports or the results of the studies within the hypothesis were not interpretable. CONCLUSIONS There is not sufficient evidence to support or refute the existence of OIH in humans except in the case of normal volunteers receiving opioid infusions. Prospective CPP clinical studies measuring ptrs and tolerances pre- and post-opioid placement with CPP non-opioid control groups are required.