Emotional distress as a mediator of the relationship between pain and disability: An experimental study

In people with chronic pain, disability is only partially explained by pain levels and emotional distress has been postulated to moderate the relationship between pain and disability in these and in other individuals. This paper reports an experimental investigation of this hypothesis with patients attending a clinical psychology department with chronic pain problems. Sections of the normal clinical interview which increased anxiety (asking about upsetting events) or reduced anxiety (asking about good events) were identified and standardized to give a naturally occurring mood induction technique. Twenty-five patients were randomly allocated to receive the anxiety increasing section of the interview as part of the experimental procedure and 25 to receive the anxiety reducing section. Both groups received the other section later in the interview. Patients were assessed before and after the experimental procedure and results demonstrated that the mood induction procedures had produced the expected effects on mood and the resulting predicted effects on disability. Experimental mood enhancement was associated with reduced levels of disability assessed by a lifting task, while mood depression resulted in greater disability. These findings strengthen the results from correlational studies and suggest methods of minimizing disability, at least in the short term.