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Somatic Symptom Disorder: DSM-5's Removal of Mind-Body Separation

A newly conceptualize diagnosis of somatic symptom disorder appears in the DSM-5; this updated terminology is the focus of this month's A to Z Mental Health Series.
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The new Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)1 updated its terms for somatic symptoms from somatoform disorders to somatic symptom disorder (SSD). About 80% of the general population reports somatic symptoms weekly.2 Unexplained somatic symptoms account for about 25% to 50% of presentations in both primary care and secondary consultations.3 However, these somatic symptoms are no longer considered “disordered” unless they are associated with significant distress and impairment (eg, abnormal thoughts, feelings, and behaviors).

The key change in the DSM-5 criteria is that an SSD diagnosis no longer requires that the somatic symptoms be medically unexplained. According to Dimsdale et al, the DSM-5 “deemphasizes the centrality of medically unexplained symptoms and defines the disorder on the basis of persistent somatic symptoms associated with disproportionate thoughts, feelings, and behaviors related to these symptoms.”4 It follows that the absence of a medical explanation for the somatic symptoms’ existence is not enough nor an appropriate criterion to diagnose a mental disorder.

Somatic symptom disorder is newly defined in the DSM-5.

Many factors contribute to SSD, such as genetic/biological vulnerability (increased sensitivity to pain); early traumatic experiences (eg, violence, abuse, and deprivation); learned behavior (eg, experiences from prior illness that were reinforced rather than other ways of expressing distress); and, cultural/social norms (devalue and stigmatize psychological suffering compared to physical suffering).5 The new chapter of SSD contains several disorders, including illness anxiety (or hypochondriasis), functional neurological symptoms (or conversion disorder), factitious disorder, and psychological factors affecting other medical conditions, such as pain.3 These newly conceptualized diagnoses have proven more useful for primary care and medical specialists than for mental health clinicians, perhaps because patients view the reporting of somatic symptoms  as a more appropriate route for seeking treatment.6

The precise prevalence of these disorders is unknown, but estimates project 5% to 7% of the general population is affected by SSD.7 The frequency of the diagnosis is believed to be higher than the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition’s (DSM-IV) somatization disorder (<1%) and lower than that of undifferentiated somatoform disorder (~19%).2,8 The 1- to 2-year prevalence estimates of illness anxiety disorder in community surveys and population-based samples range from 1.3% to 10%;9,10 and the 6-month to 1-year prevalence rates in ambulatory medical populations are 3% to 8%.11,12

Referral incidence to neurology clinics for functional neurological symptom disorder is approximately 5%; and for individual persistent conversion disorder symptoms, the incidence is around 2 to 5/100,000 per year.13,14 It is estimated that about 1% of people have symptoms that meet the criteria for factitious disorder in hospital settings.15,16 According to private insurance billing data in the United States, the prevalence of psychological factors affecting other medical conditions is more common than the other SSDs.17

There is sparse research on SSD in chronic pain patients. The lifetime rates of the diagnoses among chronic low back pain patient samples are low, and are comparable to rates found in community and primary care settings.18 The lifetime prevalence rate of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) somatoform pain disorder was 34% with a 6-month rate of 17%, which dropped to 12% and 5%, respectively, when the new criterion for the DSM-IV was applied to the diagnoses.19

Another study found that more than 95% of patients with chronic low back pain in an intensive rehabilitation setting had SSD.20 There is also evidence to suggest a correlation between pain intensity and the presence of somatization and hypo- chondriasis.21 The frequency of SSD in chronic pain patients varies from 0% to 53%.22-24

More specifically, the frequency of conversion disorder ranges from 2% to 38%.23,24 The discrepancy may be due to the subjectivity of pain, but it may also reflect how the diagnostic classification of somatization has changed over time.

The History of Somatization and Chronic Pain

The philosophical, political, and religious meanings of pain have defined individual suffering throughout history. Examples of pain, such as flogging, crucifixions, and walking barefoot through the scorching desert, appear in the oldest known religious texts. Before the 17th century,  people believed that pain symptoms, such as pseudoseizures and fits, were manifestations of evil, magic, or demons. Sufferers sought relief from sorcerers, shamans, priests, or priestesses who used herbs, rites, and ceremonies as treatments.  

In 1697, Sydenham wrote that hysterical patients often had pain and were “miserably tormented with hysterical clavus [thickening of the skin] in which there is a most vehement pain in the head.”25 In the 18th century, medical scholars and practitioners believed the motor variety of hysteria (eg, paralysis) was influenced by various reflexes, darting widely about the body. Dubois D’Amiens (1833), Brodie (1837), and Landouzy (1846) further explored the relationship between hysteria and pain and found that pain was present independent of primary symptoms.26 The 19th century became the era of motor hysteria, with an epidemic of women having brief periods of paralysis (unable to move legs and unclench fists).

The focus on functional illness shifted from the easily disproved motor side of the central nervous system to the harder-to-disprove sensory side. Around World War I, 2 new sensory symptoms—functional chronic pain and fatigue—arose and became pervasive. In the 20th century, these psychosomatic symptoms became more problematic and represented the bulk of somatization.27

Today, the media broadcasts the “the disease of the month,” which is based on the notion that consumers know more about their bodies than doctors. This behavior encourages the public to fixate on new diseases and causes a “somatic hypervigilance,” which may cause distress.28 Once medicine is able to disprove the latest sensory symptoms, new psychosomatic symptoms arise.27

Last updated on: May 16, 2017
First published on: May 15, 2017
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