Objective: To compare spontaneous, interview-based, postconcussion symptom reporting to endorsement of symptoms on a standardized questionnaire.
Participants: Sixty-one patients referred to a concussion clinic following mild traumatic brain injury.
Procedure: Patients recalled their current symptoms and problems via open-ended interview and then completed a structured postconcussion checklist.
Main outcome measures: Open-ended interview and the British Columbia Postconcussion Symptom Inventory (BC-PSI).
Results: On average, patients endorsed 3.3 symptoms (SD = 1.9) during open-ended interview and 9.1 symptoms (SD = 3.2) on the BC-PSI (P < .001). Approximately 44% endorsed 4 or more symptoms during interview compared with 92% on the BC-PSI. The percentage of patients endorsing items on the BC-PSI compared with interview was significantly greater on all 13 items. It was common for patients to endorse symptoms as moderate-severe on the BC-PSI, despite not spontaneously reporting those symptoms during the interview.
Conclusions: Clinicians need to be cautious when interpreting questionnaires and be aware of the possibility of nonspecific symptom endorsement, symptom overendorsement, symptom expectations influencing symptom endorsement, and the nocebo effect.