Early improvment and marriage are determinants of the 12-month treatment outcome of paroxetine in outpatients with panic disorder
Takashi Watanabe 1*, Mikito Ueda 1, Shin Ishiguro 1, Yuki Hayashi 1, Akiko Aoki 1, Masataka Shinozaki 1, Kazuko Kato 3, Kazufumi Akiyama 2, Kazutaka Shimoda 1
1Department of Psychiatry, Dokkyo Medical University School of Medicine, 2Department of Biological Psychiatry and Neuroscience, Dokkyo Medical University School of Medicine, 3Mental Health Clinic SAKURA-RA
Received: December 26, 2016; Revised: February 22, 2017; Accepted: March 18, 2017; Published online: March 18, 2017.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Objective: In this study, we investigated the determinants of remission and discontinuation of paroxetine pharmacotherapy in outpatients with panic disorder (PD).
Methods: Subjects were 79 outpatients diagnosed with PD who took 10–40 mg/day of paroxetine for 12 months. The candidate therapeutic determinants included the serotonin transporter gene-linked polymorphic region and the –1019C/G promoter polymorphism of the serotonin receptor 1A as genetic factors, educational background and marital status as environmental factors, and early improvement (EI) at 2 weeks as a clinical factor were assessed. The Clinical Global Impression scale was used to assess the therapeutic effects of the pharmacotherapy.
Results: Cox proportional hazards regression was performed to investigate the significant predictive factors of remission and discontinuation. EI was only a significant predictive factor of remission. EI was a significant predictive factor of remission (hazard ratio, 2.709; 95% CI, 1.177–6.235). Otherwise, EI and marital status were significant predictive factors of the discontinuation. EI (hazard ratio, 0.266; 95% CI, 0.115– 0.617) and being married (hazard ratio, 0.437; 95% CI, 0.204– 0.939) were considered to reduce the risk of treatment discontinuation. In married subjects, EI was a significant predictive factor of the discontinuation (hazard ratio, 0.160; 95% CI, 0.045–0.565). However, in unmarried subjects, EI was not a significantly predictive factor for the discontinuation.
Conclusions: EI achievement appears to be a determinant of PD remission in paroxetine treatment. In married PD patients, EI achievement also appears to reduce a risk of discontinuation of paroxetine treatment.
Keywords: paroxetine, panic disorder, early improvement, environmental factor, marital status, discontinuation, 5-HTTLPR, –1019C/G, selective serotonin reuptake inhibitor, 5-HT1A, serotonin receptor 1A, serotonin transporter