Somatic Symptom Disorders

Cross-walking DSM-IV to DSM-5

The DSM-5 category, Somatic Symptom and Related Disorders, corresponds to the Somatoform Disorders category in DSM-IV. The somatoform disorders were composed of somatization disorder, undifferentiated somatoform disorder, conversion disorder, pain disorder, hypochondriasis, body dysmorphic disorder, and somatoform disorder not otherwise specified. Overlapping symptoms and unclear treatment implications, among other things, made these diagnostic labels confusing and they were rarely used in non-psychiatric clinical practice. In an effort to facilitate a more user-friendly categorization, DSM-5 renamed the somatoform disorders as somatic symptom and related disorders, and lumped four disorders (somatization disorder, undifferentiated somatoform disorder, pain disorder, and, partially, hypochondriasis) under the new heading, somatic symptom disorder. Conversion disorder remains a discrete diagnostic entity, although some have suggested that it is better categorized as a dissociative disorder given the high rates of dissociative symptoms reported in several studies of patients with conversion disorder. Figure 24-1 delineates the transition of DSM-IV-TR categories to those found in DSM-5.

The core diagnosis in this class, somatic symptom disorder, de-emphasizes the previous focus on somatic symptoms that are medically unexplained. For many, perhaps most, patients appropriately assigned this diagnosis, MUS will, indeed, be present, but this is not required, and the emphasis is placed more so upon patients' excessive and maladaptive experiences of, and responses to, symptoms, whether they be explained or not. Some commentators fear that this modification might do more harm than good by pathologizing a large majority of the population as well as potentially missing more underlying medical etiologies of unexplained symptoms. DSM-5 field trials suggested that somatic symptom disorder would capture 26% of patients with irritable bowel syndrome or fibromyalgia, 15% of patients with cancer or heart disease, and that there would be a false-positive rate of roughly 7% among healthy people in the general population. MUS remain key features of pseudocyesis and conversion disorder, as one must demonstrate that the symptoms are not consistent with known medical pathophysiology.

Somatic Symptom Disorder

The key features of somatic symptom disorder involve persistent (i.e., more than 6 months) and excessive or disproportionate thoughts (about the seriousness of one's symptoms), feelings (high level of anxiety about health), or behaviors (excessive time and energy devoted to the health concern) associated with somatic concerns to the point that the symptoms cause a significant disruption in one's daily life. These symptoms revolve around the patient's assumption that their somatic symptoms indicate underlying illness states that have been insufficiently addressed medically. While the distinction is sometimes difficult to make, the diagnosing clinician is expected to have determined that the patient's illness beliefs lack the fixed quality of the delusions, as in delusional disorder, somatic type. If an individual lacks somatic symptoms, yet still has persistent disproportionate thoughts, feelings, behaviors, and preoccupations that he or she might be sick, that person should be assessed for illness anxiety disorder (see next heading).

While the etiology of somatic symptom disorder is poorly understood and insufficiently studied epidemiologically, limited data extrapolated from other conditions suggest that a combination of factors (e.g., physiology, personality, life experiences, health cognitions, and the degree to which people experience sensations regardless of whether they have a disease) influence the development of the disorder. Risk factors include the personality trait of neuroticism, low education and socioeconomic status, recent stressful life events, female gender, older age, unemployment, and concurrent chronic physical or psychiatric illness. The prevalence of somatic symptom disorder is likely to be higher in women than men since women report more somatic symptoms.

Illness Anxiety Disorder

While somatic symptom disorder is meant or expected to classify most individuals (~75%) who would have met criteria for the DSM-IV's category called “hypochondriasis,” illness anxiety disorder accounts for the remainder. These patients are preoccupied with the idea that they are ill or that they may acquire a serious as of yet undiagnosed medical condition. The anxiety associated with the cause, meaning, or significance of the concern (rather than the somatic symptom itself) distinguishes this disorder from somatic symptom disorder, where the concern is more about distress or disability. Reassurance, negative diagnostic work-ups, and a benign somatic course do little to alleviate the anxiety of illness anxiety disorder. Fear of illness ultimately becomes a part of the identity of the afflicted. Importantly, one can have a medical condition and have co-existing illness anxiety that is disproportionate to the severity of the condition.

Although anxiety in response to serious illness can be a normal part of human experience, disproportionate and significant severity and persistence (greater than 6 months) are felt by the authors of DSM-5 to mark it as disordered. Other specific factors include the focus of worry on one's health and/or the lack thereof (as opposed to these concerns being expressions of the more global nervous preoccupation found in generalized anxiety disorder). Likewise, any given health concern is more flexible and plausible than is generally noted in patients with somatic delusions.

Since this is a newly classified disorder, its co-morbidities, risk factors, prevalence, and clinical course remain unclear. It is thought, however, to be a chronic condition that begins in early and middle adulthood. Both genes and upbringing may serve as predisposing factors. Major life stressors, threats to one's health, and a history of abuse or serious illness in childhood may serve as triggers for development of this disorder. As with the other disorders described in this chapter, one should consider cultural beliefs that can be congruent with one's mindset before making a diagnosis.

Conversion Disorder

Conversion disorder involves a loss or change in sensory or motor function that is suggestive of a physical disorder, but that lacks evidence for a known neurological or medical condition. The diagnosis can be specified by symptom type, persistence (acute and self-limiting versus chronic), and whether it occurs with or without a psychological stressor. DSM-5 eliminates the previously held criterion that one should identify an association between symptom onset and psychologically meaningful precipitants that may have led to the disorder.

Common symptoms include reduced or absent skin sensation, tunnel vision, blindness, aphonia, weakness, paralysis, tremor, dystonic movements, gait abnormalities, or abnormal limb posturing. Conversion symptoms are not under voluntary control and are usually sustained, but the patient may be able to modulate their severity. A patient with a functional gait disturbance or a weak arm, for example, may, with intense concentration, be able to demonstrate slightly better control or strength.

The diagnosis is based not on one single finding, but on the overall clinical picture. Work-ups and investigations that reveal normal findings are not sufficient to make the diagnosis. Inconsistent neurological examinations (e.g., eliciting physical signs that become positive or negative when tested in a different way) and the occasional demonstration of normal function in the supposedly disabled body part are more specific. For example, one might observe a patient crossing a leg that he subjectively cannot lift over his good one during a conversation. In the “semi-comatose” patient, deviation of the eyes toward the ground, regardless of which side the patient lies on, can sometimes demonstrate lack of an organic disorder. The patient with functional blindness can be led around obstacles whereas the patient with conversion usually avoids them (a malingerer is more likely to bump into them). Another way to assess vision is to carefully watch the “blind” patient's eyes while taking out a roll of money or making a face at the patient. A malingerer is more likely to become oppositional or uncooperative during the examination.

Factors that support a diagnosis of conversion disorder include having a history of multiple similar somatic symptoms, an onset at a time of psychological or physical stress or trauma, and an association of dissociative symptoms (e.g., depersonalization, derealization, dissociative amnesia) at time of symptom onset. A prior medical illness is a common source of the symptom. The illness may bring secondary benefits of attention and support from loved ones. Those with seizures, for example, especially complex partial seizures (in which consciousness is preserved), are repeatedly exposed to a phenomenon that removes them from responsibility, evokes sympathy, and brings help from a loved one.

Conversion disorder can co-exist with non-idiopathic neurologic disease. Psychogenic non-epileptic seizures (PNES), for example, commonly co-exist with electrographically-confirmed epilepsy and can be difficult to discriminate. Epileptic and psychogenic non-epileptic seizures can be temporally related and brain changes resulting from repeated seizures may also facilitate the development of conversion symptoms.

In adults, the disorder is more common in women, and its onset can occur throughout life, although the onset of non-epileptic attacks may peak in the third decade and motor symptoms may peak in the fourth decade. Symptoms can be persistent or transient. While the rate of misdiagnosing conversion disorder has declined, one should proceed with caution in diagnosing conversion symptoms, since some patients will develop an organic condition that in retrospect is related to the original symptom. At the same time, an extensive review of published cases suggests that fewer than 5% of individuals diagnosed with conversion disorder are found to eventually have a medical or neurologic condition that explained their initial presentation.

The literature supports a mixed prognosis for these patients, at least in the first few years. Folks and co-workers recorded a complete remission rate of 50% by discharge from the general hospital. However, the long-term course is less favorable because many patients develop recurrent conversion symptoms (20% to 25% within 1 year). Unilateral functional weakness or sensory disturbance diagnosed in hospitalized neurological patients persisted in more than 80% (of 42 patients over a median of 12.5 years). Neurologists working in specialty clinics frequently encounter individuals with chronic movements and motor symptoms; in a recent review, more than one-third of patients had the same or worse symptoms at follow-up visits and when there was improvement, there was often incomplete resolution. Likewise, with non-epileptic attacks, the majority of studies show that 60% or more of patients continue to have non-epileptic attacks at follow-up.

Modern imaging techniques used to investigate conversion disorder have demonstrated functional neuroanatomical abnormalities in patients with conversion disorder. Some studies have suggested that conversion results from dynamic reorganization of neural circuits that link volition, movement, and perception. Disruption of these networks may occur at the stage of pre-conscious motor planning, modality-specific attention, or right fronto-parietal networks subserving self-recognition and the affective correlate of self-hood. Overall, however, the number of individuals studied has been small and no distinct pattern of functional brain activity has emerged.

Psychological Factors Affecting Other Medical Conditions

This diagnosis should be considered when an individual displays psychological traits or behaviors that adversely affect the course (by precipitating or exacerbating symptoms) or treatment of a medical condition. Examples of these “psychological factors” involve the impact of stressful life events, relationship style, personality traits, coping styles, and depressive symptoms. These qualities and phenomena should not constitute a psychiatric disorder in and of themselves, and it is only through their interaction with somatic illness that their adverse effects come to clinical attention. It is sufficient for there to be an association between the abnormal psychological symptom and the medical condition, as direct causality is difficult and unnecessary to demonstrate. Distinguishing between this diagnosis and adjustment disorder is frequently arbitrary, although we point out that the word “disorder” is conspicuously absent from psychological factors affecting medical illness. As with the other conditions described in this chapter, one should be careful to differentiate them from culturally-specific behaviors (e.g., using spiritual healers to manage illness).

Factitious Disorders

The factitious disorders include versions imposed on the self and imposed on another (formerly, “by proxy”) in DSM-5. Previously occupying a category of their own in DSM-IV, the factitious disorders are now subsumed within the somatic symptom and related disorders category, presumably because they were considered to be primarily “characterized by the prominent focus on somatic concerns and their initial presentation mainly in medical rather than mental health care settings.” Putting aside the unproductive separation of “medical” and psychiatric practice inherent in this general rationale, we note that despite this re-categorization of factitious disorder, its possible exclusive presentation with psychological features remains part of the diagnostic criteria (albeit not the subtype it formerly was). Our chapter largely treats deception syndromes (factitious disorder and malingering) as warranting separate attention from the somatic symptom and related disorders. This chapter compares and contrasts intentional and unintentional signs and symptoms below, but detailed discussions of factitious disorder and malingering can be found in Chapter 25 .