Statistics from the Swedish Social Insurance Agency show a sharp increase in the number of sick leave cases with the diagnoses Concussion, S06.0, and Postconcussional syndrome, F07.2, between the years 2010 and 2022. The reason for the increase has not been established and needs further investigation. One possible reason is that the acute phase treatment recommendations of individuals with mild traumatic brain injury have changed during the relevant time period. Future guidelines must ensure that treatment and management recommendations are based on controlled studies of an adequate population and that treatment outcomes are continuously evaluated.