Early Improvement and Marriage Are Determinants of the 12-Month Treatment Outcome of Paroxetine in Outpatients with Panic Disorder

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 [HR], 2.709; 95% confidence interval [CI], 1.177–6.235). Otherwise, EI and marital status were significant predictive factors of the discontinuation. EI (HR, 0.266; 95% CI, 0.115–0.617) and being married (HR, 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 (HR, 0.160; 95% CI, 0.045–0.565). However, in unmarried subjects, EI was not a significantly predictive factor for the discontinuation. CONCLUSION: 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.

Genetic Polymorphism of 1019C/G (rs6295) Promoter of Serotonin 1A Receptor and Catechol-O-Methyltransferase in Panic Disorder

OBJECTIVE: Family and twin studies have suggested genetic liability for panic disorder (PD) and therefore we sought to determine the role of noradrenergic and serotonergic candidate genes for susceptibility for PD in a Japanese population. METHODS: In this age- and gender-matched case-control study involving 119 PD patients and 119 healthy controls, we examined the genotype distributions and allele frequencies of the serotonin transporter gene linked polymorphic region (5-HTTLPR), −1019C/G (rs6295) promoter polymorphism of the serotonin receptor 1A (5-HT1A), and catechol-O-methyltransferase (COMT) gene polymorphism (rs4680) and their association with PD. RESULTS: No significant differences were evident in the allele frequencies or genotype distributions of the COMT (rs4680), 5-HTTLPR polymorphisms or the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients and controls. Although there were no significant associations of these polymorphisms with in subgroups of PD patients differentiated by gender or in subgroup comorbid with agoraphobia (AP), significant difference was observed in genotype distributions of the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients without AP and controls (p=0.047). CONCLUSION: In this association study, the 1019C/G (rs6295) promoter polymorphism of the 5-HT1A receptor G/G genotype was associated with PD without AP in a Japanese population.