Objective: To examine the influence of depression on postconcussion symptom reporting in patients following mild traumatic brain injury (MTBI).
Participants: Sixty patients referred to a specialty clinic following MTBI, 58 outpatients with Structured Clinical Interview for DSM-diagnosed depression, and 72 healthy community control participants.
Procedure: Participants with MTBI were divided into 2 subgroups on the basis of self-reported symptoms of depression (23 MTBI-depressed, 37 MTBI-not depressed). All participants completed a postconcussion symptom questionnaire.
Main outcome measure: British Columbia Post-concussion Symptom Inventory.
Results: There were significant differences in total reported postconcussion symptoms among all 4 groups (all P < .002; Cohen's d = 0.68-3.24, large to very large effect sizes; MTBI-depressed > depressed outpatients > MTBI-no depression > healthy controls). There were significant differences in the number of symptoms endorsed (P < .05), with the highest number of symptoms endorsed by the MTBI-depressed group, followed by depressed outpatients, MTBI-no depression, and healthy controls.
Conclusions: Patients who experience MTBIs and who have a postinjury recovery course complicated by significant depression report more postconcussion symptoms, and more severe symptoms, than (a) outpatients with depression, and (b) patients with MTBIs who do not have significant symptoms of depression.