Actually, in a recent study published in the Clinical Journal of Sport Medicine, athletes were seen to recover differently emotionally from a musculoskeletal injury then from a concussion. The athlete recovering from a concussion will be significantly fatigued with a lack of energy or vigor. The athlete with a musculoskeletal injury suffered from an elevated level of anger within the first two weeks.
You should be watching for less energy and fatigue which can often look like a depressed state in an athlete with a recent concussion. Although this research needs more replication, it appears that after a concussion, the team doctor needs to be alert to emotional, physical and mental changes in the academic, social and athletic performances of their athlete.
Read the full article 'the Psychological Edge'