About FSS and CSS


One of my primary specializations is in working with clients who have chronic medical illnesses. A large part of my clinical focus in the past decade has been with individuals suffering from functional somatic syndromes, or FSS. The term “functional somatic syndrome” is applied to multiple diseases and illnesses that share common features, most notably the presence of medically unexplained symptoms. In other words, the individual suffers from very real physical symptoms, such as pain or fatigue, in the absence of biochemical markers or imaging findings that would indicate a physiological abnormality. This is extremely frustrating for patients, who are genuinely suffering, yet may be told that their symptoms are “all in your head.” This leaves the individual with a FSS often feeling invalidated and stigmatized, in addition to suffering directly from the symptoms.

A relatively recent line of research suggests that FSS share a common biological process, however. This process is termed central sensitization, and sometimes FSS are referred to as central sensitization syndromes, or CSS. The idea behind CSS is that symptoms – such as pain, fatigue, and anxiety – are caused by hypersensitivity of neural pathways in the central nervous system. While there is no definitive understanding of why or how these neural pathways become highly sensitized, there is evidence to suggest that chronic stress and/or trauma – particularly during childhood – alters these biological pathways to result in neurological hypersensitivity.

Examples of FSS/CSS

Examples of diseases and illnesses considered to be FSS or to have a CSS component include:

  • Fibromyalgia (FMS)/myalgic encephalomyelitis (ME)
  • Chronic Fatigue Syndrome (CFS)/Systemic Exertion Intolerance Disorder (SEID)
  • Irritable Bowel Syndrome (IBS)
  • Migraine
  • Multiple chemical sensitivity
  • Temporomandibular Joint Disorder (TMJ)
  • Myofascial pain syndrome
  • Restless leg syndrome
  • Posttraumatic Stress Disorder (PTSD)

Relevance of psychotherapy

While several of these illnesses have no cure, research suggests that the quality of life of individuals with a FSS can be significantly improved with the addition of psychotherapy to medical treatment. The recommendation of psychotherapy does not imply that one’s symptoms are all psychological (or “all in your head”). In fact, psychotherapy is a recommended and empirically supported component of multidisciplinary treatment for many medical disorders, such as cancer, diabetes, stroke, traumatic brain injury, spinal cord injury, etc. Therapy can help you manage your symptoms better, develop techniques to cope more effectively with suffering, and overall increase your quality of life.

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