Abstract
The classification scheme for psychiatric diagnoses and related pain complaints has changed significantly in the most recent update to the Diagnostic and Statistical Manual of Mental Disorders, the DSM-5. This general category is now referred to as somatic symptom and related disorders, previously classified as somatoform disorders. This reorganization of diagnoses came about as these patients typically present to primary care providers and other physicians (including pain specialists) and less often to psychiatrists or psychologists. The previous classification scheme was often difficult to interpret and apply for the bulk of nonpsychiatry trained clinicians. Therefore the authors of the DSM-5 sought to reduce the total number of diagnoses in this category and eliminated many of the subdiagnoses. These disorders share somatic symptoms associated with significant distress and functional impairment. Additionally, in the DSM-IV there was a focus on unexplained medical symptoms, whereas the DSM-5 recognizes that somatic symptoms and disorders may actually coexist with diagnosed medical conditions and that psychiatric disorders can be present alongside medical conditions. The DSM-5 also seeks to reduce the negative connotation of the lack of a medical diagnosis or diagnosis of exclusion and therefore shifts focus to presence of positive symptoms. The diagnoses under this heading that generally involve some aspect of pain will therefore be discussed in more detail in this chapter, include somatic symptom disorder, conversion disorder, and factitious disorder. In addition to these diagnoses, the topic of malingering (not classified as a mental illness) will be discussed.
Keywords
conversion disorder, DSM-5, factitious disorder, malingering, somatic symptom disorder, Waddell signs
Introduction
Since the third edition of Essentials of Pain Medicine, a fifth edition of the Diagnostic and Statistical Manual of Mental Disorders was published in 2013 (henceforth referred to as DSM-5). The nomenclature has changed significantly with regard to this chapter involving the relationship between psychiatric diagnoses and pain-related complaints. Entities previously classified as somatoform disorders (e.g., somatization disorder, pain disorder, hypochondriasis, and others) have been reorganized and reclassified, and are currently characterized under the heading of somatic symptom and related disorders. This category now includes diagnoses of somatic symptom disorder, illness anxiety disorder, conversion disorder (functional neurological symptom disorder), psychological factors affecting other medical conditions, factitious disorder, other specified somatic symptom and related disorder, and unspecified somatic symptom and related disorder, while pain disorder only made an appearance in DSM-IV and does not appear again in DSM-5. These diagnoses are grouped together by the presence of physical symptoms associated with significant distress and functional impairment. These patients often present to primary care providers, as well as pain specialists, as opposed to psychiatrists/psychologists, and the reorganization of diagnoses was done for the benefit of nonpsychiatry trained clinicians. The term somatoform disorders was often confusing to providers because there was too much overlap within this group of diagnoses. Therefore the authors of the DSM-5 reduced both the number of diagnoses in this category, as well as eliminated many sub-diagnoses. In the DSM-IV, there was a focus on unexplained medical symptoms, whereas the DSM-5 recognizes that somatic symptoms and disorders may actually accompany diagnosed medical conditions, and that psychiatric disorders can be present alongside medical diagnoses. There has been difficulty relying on a diagnosis of exclusion as the basis for a psychiatric disorder, in addition to the inappropriateness of making a psychiatric diagnosis merely because a medical diagnosis cannot be made. A negative connotation often accompanies the lack of a medical diagnosis, and patients may feel they are not being understood or believed. Again, the DSM-5 seeks to change this by focusing on the presence of positive symptoms: “however, medically unexplained symptoms remain a key feature in Conversion Disorder and Pseudocyesis (a false belief of being pregnant that is associated with objective signs and reported symptoms of pregnancy, classified as an Other Specified Somatic Symptom and Related Disorder) because it is possible to demonstrate definitively in such disorders that the symptoms are not consistent with medical pathophysiology.” It is important to consider entities that influence these types of disorders, including biological predisposition to pain (e.g., fibromyalgia), prior life experiences (particularly those of the emotionally traumatic variety), secondary gain, and/or cultural differences regarding somatic complaints and pain. In this chapter, we will cover somatic symptom and related disorders that are pertinent to pain management, including somatic symptom disorder, conversion disorder, and factitious disorder, as well as malingering.
Somatic Symptom Disorder
In the DSM-IV, patients with somatoform symptom disorder may have been classified as having somatization disorder (an often confusing diagnosis), hypochondriasis, or pain disorder. Undesired and unpleasant bodily experiences may unfortunately be common features of everyday life, with up to 60% to 80% of the general population experiencing one or more somatic symptoms in any given week. Typically these symptoms include pain, fatigue, nausea, imbalance, dystonia, dyspnea, and/or paresthesias. For the vast majority of people, these episodes are transient. A minority of individuals decides to seek medical help, typically when the experience persists, becomes severe or disabling, or is accompanied by the fearful belief that the sensation is a symptom of a more significant medical diagnosis.
The approach to patients with many symptoms must include a thorough history and examination, consisting at a minimum of medical history, individual and family psychiatric history, social history, current medications, and laboratory or diagnostic imaging results. The somatic symptoms can be numerous and overwhelming for the time-constrained clinician. Objective physical examination findings are often lacking, and laboratory results are typically unrevealing. Nonetheless, it remains imperative to rule out general medical conditions that may manifest with vague somatic symptoms. It has become increasingly common in pain management for patients to present with more than the typical complaints of back and neck pain, and the pain practitioner must either be comfortable diagnosing and managing these other types of pain, or have a plan for referral to another physician with expertise in the area of the complaint.
The DSM-5 diagnosis of somatic symptom disorder places greater emphasis on the presence of positive symptoms (often unpleasant or distressing symptoms and resultant abnormal behaviors), as opposed to the lack of a medical explanation for the patient’s complaints. The dysfunctional way of thinking and behaving in response to these positive symptoms, and not merely the presence of the complaints themselves, is what distinguishes this diagnosis. According to the DSM-5 diagnostic criteria, patients with somatic symptom disorder typically have multiple symptoms that are distressing or result in significant disruption of daily life (Criterion A), although pain alone is enough to satisfy this criterion. Individuals with this diagnosis often have excessive thoughts, feelings, or behaviors related to the somatic symptoms, as manifested by either disproportionate and persistent thoughts about the seriousness of one’s symptoms, persistently high level of anxiety about health or symptoms, or excessive time and energy devoted to the these symptoms (Criterion B). Patients who persist in searching for a medical cause for their functional symptoms risk invasive diagnostic procedures and unnecessary surgery, in addition to the fact that these tests rarely alleviate any concerns, and the unwarranted costs of these examinations may further strain limited medical resources. Patients do not need to have the same complaint continuously, but they must have a symptom present chronically (Criterion C). If the primary complaint is pain, then the somatic symptom disorder should be specified with predominant pain, which was previously classified as pain disorder in the DSM-IV. Table 7.1 lists the diagnostic criteria for somatic symptom disorder.
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According to the DSM-5, the differential diagnosis for somatic symptom disorder should also include:
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Depressive disorders—where poor mood is prominent
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Panic disorder—more acute
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Generalized anxiety disorder—patients worry about many things, but not often illness
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Illness anxiety disorder—worries about health with minimal somatic complaints
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Conversion disorder—predominant complaint is a loss of function rather than the associated distress
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Unrecognized organic disease
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Substance abuse
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Cognitive dysfunction
Somatic symptom disorder is more common in women than men (as was somatization disorder), with a possible prevalence of 5% to 7% in adults.
Conversion Disorder (Functional Neurological Symptom Disorder)
The hallmark of conversion disorder is the presence of neurological symptoms that are incompatible with neurological pathophysiology. There may be one or several symptoms, usually involving sensory or motor function. Motor symptoms or deficits include impaired coordination or balance, paralysis, aphonia, dysphagia, and/or urinary retention. Sensory symptoms include loss of touch or pain sensation, diplopia, blindness, deafness, and/or hallucinations. Symptoms may also include seizures or convulsions, or episodes of unresponsiveness. Presenting symptoms may seem implausible and may strongly depend on the patient’s level of education. Conversion symptoms typically do not conform to anatomic pathways and physiologic mechanisms but instead follow the individual’s conceptualization of a condition. For example, “paralysis” may involve an inability to perform a specific movement or move an entire body part, rather than a deficit corresponding to patterns of motor innervation. There may be unacknowledged strength in antagonistic muscles, normal muscle tone, and intact reflexes. Electromyography (EMG), evoked responses of vision and hearing, fundoscopic examinations, pulmonary function tests, and barium swallows are examples of tests that should be normal. A diagnosis of conversion disorder should only be made after a thorough medical investigation has been performed to rule out an etiologic, neurologic, or general medical condition. Performing repeated exams, changing the examiner, or use of distracting techniques may be helpful in elucidating somewhat feigned symptoms. A few examples include Hoover sign, in which weakness of hip extension returns to normal strength with contralateral hip flexion against resistance, weakness of ankle plantar flexion in a patient that can walk on his toes, or alteration in a functional tremor when a patient is asked to copy an examiner’s movements with the nontremulous hand, such that the functional tremor changes or entrains to the unaffected extremity. With regard to psychogenic seizures, the presence of closed eyes with resistance to opening may be present. True disability may result from disuse of extremities. A general medical etiology for an apparent diagnosis of conversion disorder may take years to manifest; therefore it is important to reevaluate this diagnosis periodically. The presence of a neurologic condition does not preclude a diagnosis of conversion disorder, and as many as one-third of individuals with conversion symptoms have a current or prior neurological diagnosis. Conversion disorder may be diagnosed in the presence of a neurological disorder if the symptoms are not fully explained given the severity of the organic diagnosis. Table 7.2 lists the diagnostic criteria for conversion disorder. A history of trauma or stress may be present, but is not necessary for the diagnosis of conversion disorder. Dissociative symptoms may manifest, particularly during acute episodes. Patients with conversion disorder may or may not be feigning symptoms, but this is not part of the diagnostic criteria for the disorder (as it was in the DSM-IV).
