Changes in pain catastrophizing following physical therapy for musculoskeletal injury: the influence of depressive and post-traumatic stress symptoms.

PURPOSE: The aim of the present study was to investigate the factors that influence the change in pain catastrophizing during the course of a physical therapy intervention for musculoskeletal injury.
METHODS: 187 clients enrolled in a 7-week physical therapy intervention were divided into four mutually exclusive groups on the basis of a pre-treatment assessment: (1) clients whose pre-treatment catastrophizing scores and measures of mental health problems were below clinical threshold, (2) clients whose pre-treatment catastrophizing scores were above clinical threshold but who scores on measures of mental health problems were below clinical threshold, (3) clients whose pre-treatment catastrophizing scores were above clinical threshold and whose scores on measures of mental health problems were also above clinical threshold, and (4) clients whose pre-treatment catastrophizing scores were below clinical threshold but whose scores on measures of mental health problems were above clinical threshold.
RESULTS: The most prevalent risk profile consisted of clients with high levels of pain catastrophizing and high mental health problems (37 %), followed by the low catastrophizing and low mental health problems profile (35 %), the high catastrophizing and low mental health problems profile (16 %), and low catastrophizing and high mental health problems profile (10 %). Clients were considered non-responders if their post-treatment catastrophizing score remained above clinical threshold following treatment. Chi square analyses revealed a significantly higher proportion of non-responders in the high catastrophizing and mental health problem group than in any other group.
CONCLUSIONS: The presence of mental health symptoms markedly reduces the effectiveness of physical therapy for reducing catastrophizing scores. The 'risk value' of high catastrophizing scores thus appears to vary as a function of the presence or absence of mental health symptoms. The findings argue for the inclusion of measures of mental health problems in the routine screening of individuals treated in physical therapy.