Preexisting Conditions Can Complicate Concussion Diagnosis

soccer concussion
soccer concussion
Girls with a history of a psychiatric condition, substance abuse, or ADHD were more likely to report concussion-like symptoms.

Determining when it is safe to allow a previously-injured athlete to return to activity can be a complicated decision, as recovery from concussion can be affected by both patient behaviors and environmental factors. For this reason, an asymptomatic baseline should be established.

However, baselines may also be difficult to nail down — especially in athletes with preexisting conditions.

Research published in JAMA Pediatrics highlights the problems that clinicians may face when trying to develop a baseline in subjects with a history of preexisting conditions, which may include a psychiatric condition, ADHD, or substance abuse, among others. Having these conditions raises the likelihood that an athlete will report symptoms similar to post-concussive syndrome in the absence of actual concussion.

Grant L. Iverson, PhD, of Harvard Medical School, and colleagues conducted a cross-sectional, observational study of 31,958 high school student athletes with no history of concussion in the prior six months. All athletes had completed preseason baseline testing.

The researchers found that symptom reporting was more common in girls than boys, with 28% of girls reporting a symptom burden that resembles the ICD-10 diagnosis of postconcussional syndrome (PCS) compared to 19% of boys. Sixty to 82% of boys and 73 to 97% of girls with pre-existing conditions reported one or more symptoms, and those with preexisting conditions were more likely to endorse a symptom that resembled PCS (21%-47% boys; 33%-72% girls).

In boys, the strongest predictor for symptom reporting was prior treatment of a psychiatric condition, followed by a history of migraines. In girls, the strongest predictors were prior treatment of a psychiatric condition, substance abuse, and ADHD. Interestingly, the weakest independent predictor of symptom reporting in either sex was a history of prior concussions.

“When managing a student athlete with a concussion, it has been widely noted that the athlete should be ‘asymptomatic’ at rest and with exercise before returning to sports, and sometimes athletes are kept out of school for prolonged periods while they wait for symptoms to resolve, which could have negative consequences for their academic, social, and emotional functioning and contribute to symptom reporting,” the authors wrote. “These results reinforce that ‘asymptomatic’ status after concussion can be difficult to define.”

The researchers stressed that consideration of a patient’s sex and preexisting health conditions could help prevent misinterpretation of concussion symptoms in student athletes.


  1. Iverson GL et al. JAMA Pediatr. 2015; doi:10.1001/jamapediatrics.2015.2374.