Clinical data are producted which appear to show that the response to therapy of myofascial pain dysfunction syndrome (MPDS) is much less favorable when the patient has been involved in a road traffic or similar accident which precipiated the condition. Reasons for this difference and the differences between postinjury MPDS and nonpostinjury MPDS patients may be a consequence of litigation and, in addition, may be due to the personality of the patient. Evidence to support this hypothesis is seen when the condition is compared with such disorders as low back pain. Further research is needed to explore the etiology and treatment implications of these differences.