Objective: Comorbidity among personality disorders is widely considered problematic. The validity of one proposed solution, diagnostic hierarchies, was investigated in the current study with respect to borderline, schizotypal, avoidant, and obsessive-compulsive personality disorders.
Method: One approach used discriminant functions, derived from multiple psycho-social domains, that were used to classify comorbid individuals from the Collaborative Longitudinal Personality Disorder study (CLPS) to explore the possibility of hierarchical precedence of one personality disorder over another. A second approach examined the incremental increase in R(2)-value in predicting functioning and personality provided by each diagnosis over each other diagnosis.
Results: Obsessive-compulsive personality disorder was consistently subordinate to other diagnoses, whereas other indications of hierarchical relationships were domain-specific.
Conclusion: Results indicate minimal support for an over-arching hierarchical pattern among studied personality disorders, and suggest the inclusion of all relevant diagnoses in clinical practice.