Brief ReportsPostconcussion Syndrome A Diagnosis of Past Diagnostic and Statistical Manual of Mental DisordersMcIntyre, McKyla MD; Amiri, Mohammadreza PhD; Kumbhare, Dinesh MD, PhD, FRCPC, FAAPMRAuthor Information From the Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada (MM, MA, DK); and University of Toronto, Department of Medicine, Division of Physical Medicine and Rehabilitation, Toronto, Ontario, Canada (DK). All correspondence should be addressed to: Dinesh Kumbhare, MD, PhD, FRCPC, FAAPMR, 550 University Ave, Suite 7-131, Toronto, ON, Canada M5G 2A2. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article. American Journal of Physical Medicine & Rehabilitation: February 2021 - Volume 100 - Issue 2 - p 193-195 doi: 10.1097/PHM.0000000000001586 Buy Metrics Abstract After concussion, a subset of patients have persistent symptoms that are functionally limiting and may be difficult to treat. These symptoms were previously captured in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) under the diagnosis of “Post-Concussion Syndrome.” However, in the recently published fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, postconcussion syndrome has been eliminated. The elimination of “Post-Concussion Syndrome” moves the Diagnostic and Statistical Manual of Mental Disorders further away from congruence with the International Classification of Diseases (ICD-10) with respect to the classification of postconcussion symptomology. Although this change likely had the positive effect of reducing misdiagnoses of symptoms due to other causes, the authors highlight the potential issues surrounding the elimination of postconcussion syndrome in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. This opinion piece also emphasizes the multiple diagnostic and therapeutic challenges that may result for those involved in the treatment of, or research regarding, concussion patients with persistent symptoms. Future revisions that provide clear clinical diagnostic criteria may be beneficial. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.