Impact of personality status on the outcomes and cost of cognitive–behavioural therapy for health anxiety

BACKGROUND Health anxiety, hypochondriasis and personality disturbance commonly coexist. The impact of personality status was assessed in a secondary analysis of a randomised controlled trial (RCT). AIMS To test the impact of personality status using ICD-11 criteria on the clinical and cost outcomes of treatment with cognitive-behavioural therapy for health anxiety (CBT-HA) and standard care over 2 years. METHOD Personality dysfunction was assessed at baseline in 444 patients before randomisation and independent assessment of costs and outcomes made on four occasions over 2 years. RESULTS In total, 381 patients (86%) had some personality dysfunction with 184 (41%) satisfying the ICD criteria for personality disorder. Those with no personality dysfunction showed no treatment differences (P = 0.90) and worse social function with CBT-HA compared with standard care (P<0.03) whereas all other personality groups showed greater improvement with CBT-HA maintained over 2 years (P<0.001). Less benefit was shown in those with more severe personality disorder (P<0.05). Costs were less with CBT-HA except for non-significant greater differences in those with moderate or severe personality disorder. CONCLUSIONS The results contradict the hypothesis that personality disorder impairs response to CBT in health anxiety in both the short and medium term.