Inverse comorbidity: the power of paradox in the advancement of science

Research on comorbidity and multimorbidity is finally receiving the attention it deserves, particularly considering the magnitude and impact they have on health and the delivery of healthcare [1,2]. Numerous studies have demonstrated that individuals with Down’s syndrome, Parkinson’s disease, schizophrenia, diabetes, anorexia nervosa, Alzheimer’s disease, allergy related diseases, multiple sclerosis or Huntington’s disease (among other health problems) are protected against many forms of cancer, including solid tumors, smoking-related tumors and prostate cancer. This apparent anti-cancer effect, which we have termed inverse cancer comorbidity, has been observed in many serious CNS and immune disorders, and is the subject of active research [3?5].