1 Department of Health, Kinesiology, & Applied Physiology, Concordia University, Montreal, Quebec, Canada.
2 School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada.
3 Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada.
4 Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, USA.
5 Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA.
6 Mass General for Children Sports Concussion Program, Waltham, MA, USA.
7 Department of Physical Medicine and Rehabilitation, Schoen Adams Research Institute at Spaulding Rehabilitation, Charlestown, MA, USA.
8 Department of Psychology, University of Rhode Island, Kingston, RI, USA.
9 Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
10 Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada.
11 School of Health, Concordia University, Montreal, Quebec, Canada.

This secondary analysis examined the association between preexisting mental health conditions and clinical recovery trajectories in adolescents with concussion. Adolescents (13-17; n = 1238) completed clinical assessments (Post-Concussion Symptom Inventory [PCSI] =48 hours postinjury; PCSI/ Pediatric Quality of Life [PedsQL] for 3 months) and were categorized into control, anxiety, depression, or combined anxiety/depression groups. Acute outcomes were analyzed using analysis of variance or ?², whereas linear and logistic regression analyzed recovery trajectories. A main effect of group was present for acute symptom scores (P = .03), but post-hoc testing revealed no significant comparisons. Main effects of group and time were observed for PCSI and PedsQL outcomes (P < .007), but interaction effects were nonsignificant. The combined anxiety/depression group reported more symptoms, worse quality of life, and had greater odds of experiencing persistent postconcussion symptoms (defined as =3 new/worse symptoms at 4 weeks; OR = 2.31, 95% CI = 1.18-4.67, P = .02) in univariate models. However, multivariable models found no association between preexisting mental health conditions and the presence of PPCS (P = .62). Preexisting mental health conditions were associated with similar longitudinal trajectories but higher symptom and lower quality of life scores overall, highlighting their importance in adolescent concussion management.