Psychosocial Vulnerability and Early Life Adversity as Risk Factors for Central Sensitivity Syndromes.

The aim of this narrative review of the epidemiology of central sensitivity syndromes is to provide a summary of the role of early life adversity and psychosocial / psychological factors, in the epidemiology of six main syndromes: (i) fibromyalgia / chronic widespread pain; (ii) headache / migraine; (iii) irritable bowel syndrome; (iv) temporomandibular joint disorder; (v) interstitial cystitis; and (vi) endometriosis / vulvodynia / chronic pelvic pain. The occurrence of each of the above syndromes vary between each other, and between studies. Prevalence ranges from interstitial cystitis, with a prevalence of approximately 14.5 per 100,000, to headache, with some estimates of lifetime prevalence to be around 66%. Precise risk estimates vary between studies, conditions, and exposures, although there is consistent evidence to suggest an association between early life adversity and central sensitivity syndromes (based on the six syndromes under investigation). In further support of this, a number of studies have also demonstrated dose-risk associations. There is also considerable consistency in the literature to suggest a strong association between negative psychological and psychosocial factors, and the occurrence of central sensitivity syndromes and, again, there is some evidence of a dose-risk relationship. The majority of studies in this field are cross-sectional or retrospective in design, and caution is advised when interpreting results. It is possible - indeed there is some evidence - that some findings may be subject to recall bias, and reverse causation is also a potential concern. However, there are also a number of prospective studies which provide more robust evidence.