Effort, exaggeration and malingering after concussion.

Although most individuals who suffer a mild traumatic brain injury have complete recovery, a number experience persistent symptoms that appear inconsistent with the severity of the injury. Symptoms may be ascribed to malingering, exaggeration or poor effort on cognitive testing. The purpose of this paper is to propose that previously unconsidered factors, informed by social psychology and behavioural economics, can appear as 'symptom magnification' or 'poor effort', which are incorrectly interpreted as the result of a conscious process. These are complex and multi-determined behaviours with a unique differential diagnosis which have important implications for research, evaluation and treatment.