SPECIFICITY OF MMPI CLUSTER TYPES TO CHRONIC ILLNESS

Cluster analysis derived MMPI profile types were compared for three di stinct illness populations: chronic low back pain (CLBP), mixed headac he (HA), and cardiac disease (CD). Results replicated previous finding s in the chronic pain and cardiac literatures. Differences between dia gnostic groups and genders were found for the prevalence of the derive d MMPI profile types. Results indicated that, in males, the two chroni c pain groups had similar profile types and similar relative frequenci es of these types, but both differed from the CD sample. The chronic p ain groups tended to have a greater number of patients with pathologic al and distressed MMPI profile types and a lesser representation in th e subclinical profile type compared to the CD sample. Similar findings were obtained for females, though the CLBP group tended to have a hig her frequency of highly distressed, pathological profiles than either the HA or CD groups. Results suggested that the MMPI may be a measure of response to illness rather than reflecting predisposing personality types for any given illness and that the higher frequency of highly d istressed profiles in the chronic pain samples reflects the increased suffering of those populations compared to other illnesses.