Impact of personality disorder comorbidity on cognitive-behavioral therapy outcome for mood and anxiety disorders: results from a university training clinic

This study examined the impact of co-occurring personality disorder (PD) pathology on mood and anxiety symptom improvement in response to non-manualized, short-term, cognitive-behavioral therapy (CBT) delivered by trainees. The sample comprised 305 adult outpatients treated individually for mood (unipolar depression) and anxiety disorders [generalized anxiety disorder (GAD), panic disorder, social anxiety disorder (SAD), specific phobia, obsessive-compulsive disorder (OCD)] by doctoral students within a university training clinic. After comprehensive assessment of psychopathology, symptom-specific measures were administered at pre- and end-treatment. Both magnitude of disorder-specific mood and anxiety symptom change, as well as treatment outcome classification (via reliable change and clinical significance indices) were utilized to assess treatment response. Results indicated that patients treated for depression, GAD, panic disorder, SAD, and specific phobias evidenced significant reductions in symptoms, irrespective of PD presence, and there was no interaction between PD comorbidity and level of symptom improvement. Among patients treated for OCD, PD pathology negatively impacted OCD symptom improvement. When treatment outcome was determined categorically, PD presence had a deleterious effect on clinical recovery only among patients treated for GAD. Neither the number of PD diagnoses nor PD cluster type moderated results. In conclusion, in most instances (with the exception of GAD and OCD patients), individuals with PDs treated by graduate student trainees within a university training clinic experienced significant mood and anxiety symptom improvement in response to short-term CBT, and these improvements were comparable to those without co-occurring PDs.