Illness Denial in Medical Disorders: A Systematic Review

Introduction: Illness denial pertains to medical patients who do not acknowledge the presence or severity of their disease or the need of treatment. Objective: This systematic review was performed to clarify the clinical role and manifestations of illness denial, its impact on health attitudes and behavior, as well as on short- and long-term outcomes in patients with medical disorders. Methods: The systematic search according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines was conducted on PubMed, Scopus, and Web of Science. Results: The initial search yielded a total of 14,098 articles; 176 studies met the criteria for inclusion. Illness denial appeared to be a relatively common condition affecting a wide spectrum of health attitudes and behavior. In some cases, it may help a person cope with various stages of illness and treatment. In other situations, it may determine delay in seeking treatment, impaired adherence, and reduced self-management, leading to adverse outcomes. The Diagnostic Criteria for Psychosomatic Research (DCPR) were found to set a useful severity threshold for the condition. An important clinical distinction can also be made based on the DCPR for illness denial, which require the assessment of whether the patient has been provided with an adequate appraisal of the medical situation. Conclusions: This systematic review indicates that patients with medical disorders experience and express illness denial in many forms and with varying degrees of severity. The findings suggest the need for a multidimensional assessment and provide challenging insights into the management of medical disorders.