**5. Conclusions**

Between a third and a half of GPs lack confidence in diagnosing or managing ME/CFS, or dispute its existence as a genuine clinical entity. A similar proportion of ME/CFS patients express dissatisfaction with the primary medical care they have received, and experienced marked diagnostic delay when they first fell ill. These proportions have changed little over recent years, and similar conclusions have been reached across the range of geographical locations where these matters have been investigated. This conclusion renders problematic attempts to determine the prevalence of ME/CFS, and hence its economic impact. In addition, diagnostic delay is associated with severe disease and poor prognosis, and the likelihood of increased costs.

**Author Contributions:** Conceptualisation, all authors; methodology, D.A.H. and D.F.H.P.; validation, all authors.; formal analysis, D.F.H.P.; investigation, D.A.H., D.F.H.P. and X.W.-S.; resources, D.A.H., D.F.H.P. and X.W.-S.; writing—original draft preparation, D.F.H.P.; writing—review and editing, J.C., D.F.H.P., J.-D.d.K., D.A.H. and L.G.; visualization, all authors.; project administration, D.F.H.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding. EUROMENE receives funding for networking activities from the COST programme (COST Action 15111), via the COST Association.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** No new data were created or analysed in this study. Data sharing is not applicable to this article.

**Conflicts of Interest:** The authors declare no conflict of interest.
