Chronic Pain Syndrome vs Somatic Symptom Disorder

The College of Physicians and Surgeons of Ontario policy states that “physicians must only practice in the areas of medicine in which they are educated and experienced.”

Chronic Pain specialists are often encountering challenges related to the scope of practice in both clinical and legal fields. It is not surprising given the complexity of chronic pain, its biopsychosocial phenomena and interdisciplinary approaches.

In this essay, I will try to differentiate the two most commonly confused entities, Chronic Pain Syndrome and Somatic Symptom Disorder.

The diagnosis of chronic pain is based on syndrome analyses and recommendations of the International Association for the Study of Pain (IASP). The IASP defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” The definition of chronicity is not bound. Chronic pain was traditionally defined by the length of time that pain persists, but a time-based approach ignores many other essential features. Attempts to conceptualize resulted in more confusion. The IASP currently defines chronic pain as “pain without apparent biological value,” pain “that has persisted beyond the normal tissue healing time . . . as determined by common medical experience,” and (or) as “a persistent pain that is not amenable, as a rule, to treatments based upon specific remedies.”

The traditional view on the Chronic Pain Syndrome (CPS) is a presence of pathological conditions that for poorly understood reasons resulted in complex neuropsychological changes in the central nervous system leading to physical and emotional suffering and social dysfunction. The chronic pain syndrome construct was delineated in 1987 when it was argued that chronic pain syndrome, as opposed to chronic pain, “has the added component of certain recognizable psychological and socioeconomic influences.” The presence of at least four of the following eight characteristics was said, by the American Medical Association (AMA), to establish the diagnosis of chronic pain syndrome:

• Duration (more than six months)

• Dramatization

• Drugs

• Despair

• Disuse

• Dysfunction

• Diagnostic dilemma

• Dependence on others and/or on passive physical therapy

 The American Medical Association (AMA) stated that CPS has its origin in both iatrogenic factors, such as prolonged use of passive physiotherapy modalities and prolonged inactivation, and nomogenic factors (nomogenesis refers to abnormal illness behaviour functionally related to social legislation that rewards complaints of pain, suffering, and disability). CPS is a biopsychosocial chronic, and, in many cases, irreversible condition. Potentially noxious event, particularly if occurred in certain stressful situations (e.g., trauma, surgery, assault, motor vehicle accident), coupled with neuropsychological traits or overt psychopathology and amplified by social factors (e.g., low level of education, substance dependency, low income job) may create negative loop of suffering, pain behavior and disability. Pain is a function of brain, and in this construct the chronic pain syndrome is a disease of the central nervous system with its somatic (e.g., regional or diffuse pain, decreased range of motion,  sensory and motor abnormalities), psychological (e.g., depression, catastrophizing, poor sleep, personality changes, memory loss) and social (e.g., loss of income, social withdrawal) aspects. Conceivably, social contracts pay a significant role in the development and maintaining of the chronic pain syndrome. However, on the individual level, the affected individual has a lower quality of life than a patient with an acute myocardial infarct. This condition may result in complete vocational and social disability.

Although the AMA clearly stated that chronic pain syndrome does not constitute a psychiatric disorder, the diagnosis is often equated with the psychiatric diagnosis of pain disorder associated with psychological factors.

Notwithstanding the relevance of CPS as the diagnosis, in some instances, the biomechanical derangement cannot be defined based on the available clinical and other supporting evaluations. For example, low-velocity car accidents have minimal impact on the musculoskeletal system. These injuries have similar or less probability of creating severe lasting anatomical damage than a minor domestic mishap. However, the context is different, which by itself may trigger subsequent development of widespread pain and psychological symptoms. To address this conundrum, the American Psychiatric Association (APA), introduced Somatic Symptom Disorder (SSD) with predominant Pain into DSM-V. SSD was previously known as Pain Disorder or Somatization Disorder. Here are the actual diagnostic criteria as set out on page 311 of DSM-5:

Somatic Symptom Disorder 300.82 Diagnostic Criteria

A.  One or more somatic symptoms that are distressing or result in significant disruption of daily life. B.  Excessive thoughts, feelings, or behaviours related to the somatic symptoms or associated health concerns as manifested by at least one of the following:

Disproportionate and persistent thoughts about the seriousness of one’s symptoms.

Persistently high level of anxiety about health or symptoms.

Excessive time and energy devoted to these symptoms or health concerns.

C.  Although anyone somatic symptom may not be continuously present, the state of being symptomatic is persistent (typically more than six months).

With predominant pain (previously pain disorder): This specifier is for individuals whose somatic symptoms predominantly involve pain.

The similarity between CPS and SSD is evident. Both conditions are related to chronic regional or widespread pain that is disproportional to the inciting event or illness and includes psychosocial problems and dysfunction.

As a chronic pain specialist, I encounter and treat patients with either CPS or SSD. In many cases, the approach is similar and encompasses regular meetings and counselling, careful pharmacological management and allied health support (e.g., sleep hygiene, nutritional advice, alleviation of fear to inflict more damage with exercises). While interventional approaches may be considered in CPS, only after addressing psychosocial burdens, these methods are contraindicated for SSD patients. Invasive procedures reinforce negative beliefs related to somatic complaints and fixation.

Generally speaking, a presence or absence of anatomical problem can differentiate CPS from SSD. CPS includes a significant biomechanical component (e.g., subluxation of the cervical facet joint, herniated lumbar disc) that was not adequately and effectively treated on acute or subacute stages and, therefore, progressed into biopsychosocial derangement. SSD is a mental health condition that has maladaptive behavioural expressions. It is a diagnosis by exclusion of other possible medical and/or mental disorders. Although a chronic pain specialist may and should offer help to these patients, expert opinion and therapeutic input of a psychologist and/or psychiatrist is invaluable for both clinical and medicolegal purposes.