Introduction: The present study examined the effects of pain chronicity on the responsiveness of psychosocial variables to intervention for whiplash injuries.
Methods: Participants (N = 75) were work disabled patients with a diagnosis of Whiplash Grade II and were clients in a 10-week community-based, psychosocial intervention aimed at facilitating return to work. Individuals were classified as subacute (4-12 weeks; N = 25), early chronic (3-6 months; N = 25), and chronic (6-18 months; N = 25). Patients in the three groups were matched on sex (13 men, 12 women) and age (+/-2 years). Patients completed measures of pain severity, self-reported disability, pain catastrophizing and fear of movement at pre-treatment, mid-treatment and post-treatment.
Results: Return to work rates were 80, 72 and 32% for the subacute, early chronic and chronic groups, respectively. Individuals in the chronic group, compared to individuals in the subacute or early chronic groups, had significantly more elevated pre-treatment scores on measures of pain catastrophizing, F(2, 74) = 9.6, P < .001, and fear of movement, F(2, 74) = 3.4, P < .05. The magnitude of treatment-related reductions in catastrophizing, fear of movement and pain intensity was comparable across groups. However, individuals who were absent from work for more than 6 months showed the least amount of change in self-reported disability through the course of treatment.
Conclusions: The findings suggest that self-reported disability is particularly resistant to change as the period of work disability extends over time. The findings emphasize the importance of early intervention and the need to develop strategies that specifically target disability beliefs in patients with whiplash injuries.