TABLE 2.

Factors Associated With Delayed Recovery or Poor Outcome^a

Indicator	Representative References	Commentb
Increased age at injury (>60)	(88)	True of all injury severities.
Premorbid psychiatric illness	(89, 90)	Depression, anxiety, and substance abuse are common.
Development of psychiatric illness after injury (e.g., depression, posttraumatic stress disorder)	(91–95)	Fairly consistent association between axis 1 diagnosis and increased levels of postconcussive symptoms and other outcome measures.
Compensation or litigation	(68, 96–98)	Not a universal finding. Association should not be misinterpreted as causation.
Repetitive injuries	(64, 99, 100)	Evidence is somewhat indirect and tentative—comes from both sports injury literature and early emergency department populations (64, 71).
Selected polymorphic alleles (e.g. ANKK1, APOE e4)	(2, 101, 102)	Several large ongoing studies should shed further light on this.
Abnormal acute neuroimaging	(89, 103, 104)	“Complicated MTBI” has outcomes more similar to moderate traumatic brain injury (TBI).
Expectation of poor outcome	(105, 106)	Expectation of poor outcome or severity of complications is associated with poor recovery.
Extracranial injuries and high initial symptom load	(87)	Extracranial injuries may prolong need for treatment and delay return to work but not necessarily increase postconcussive symptoms (80).

^aAdapted from McAllister (2).

^bMTBI, mild traumatic brain injury.