Personality disorders and response to medication treatment in panic disorder: a 1-year naturalistic study

Objective: In this naturalistic and prospective study, personality was assessed in patients with panic disorder (PD), in order to evaluate whether personality features negatively influence the outcome of pharmacological treatment. Method: Before drug treatment, PD was diagnosed with the Structured Clinical Interview for DSM-IV disorders and personality was assessed with the Structured Interview for DSM-IV Personality Disorders. Moreover, all patients were evaluated with the SCL-90, the Ham-A and Ham-D. Then, patients were randomly treated with paroxetine (33.5 +/- 13.3 mg/day) or citalopram (34.7 +/- 15.2 mg/day) and were followed at monthly intervals for 1 year. Absence of full and limited-symptom attacks, anticipatory anxiety, phobic avoidance and depression for 3 months was used to establish remission. The effect of personality traits on each symptom domain was evaluated. Results: Seventy-one patients completed the study. Remission rate was 76% for panic attacks and 46% for complete remission. When the effects of age, gender, age of onset and duration of PD, baseline SCL-90 phobic anxiety, Ham-A and Ham-D scores, Axis I comorbidity and the SIDP traits on remission were analyzed in a logistic regression, only borderline traits negatively influenced remission of panic attacks (OR=0.69; 95% CI=0.49-0.96;p=0.03), where as the number of traits of each personality Cluster and the total number of SIDP traits did not affect the outcome of treatment. Conclusions: This study suggests that in PD patients, borderline features may negatively influence the response to monotherapy with SSRI drugs; therefore, other treatment strategies (i.e., combination of SSRI with psychotherapy) are needed to obtain remission in these patients.