Differences between axes depend on where you set the bar: associations among symptoms, interpersonal relationship and alexithymia with number of personality disorder criteria.

Personality disorders are better understood as entities that vary according to severity along specific domains rather than a phenomenon separate from and unrelated to Axis I disorders. This study explores whether patients who were rated as having greater numbers of personality disorder traits reported greater levels of interpersonal problems, psychiatric symptoms, and alexithymia. The sample was composed of 506 consecutive patients assessed in a private outpatient center who were administered the SCID-II Symptom-Checklist (SCL-90-R), Inventory of Interpersonal Problems (IIP-47), and Toronto Alexithymia-Scale (TAS-.20). Based upon the number of personality disorder traits identified in the SCID, participants were classified into five groups: 0-4, 5-9, 10-14, 15-19, and 20 or more personality disorder traits met. Comparisons between groups revealed that symptom severity and levels of interpersonal problems increased between groups as the number of personality disorder traits increased. After covarying for symptom severity, there were no significant between-groups differences for levels of alexithymia. Findings are consistent with the claims that the simple Axis I-Axis II distinction is not an optimal strategy to understand personality pathology. It instead may be more fruitful to consider group differences in terms of numbers of personality disorder traits met.