Fluoxetine treatment of depressed patients with comorbid anxiety disorders

Abstract

Major depression with comorbid anxiety disorder is associated with poor antidepressant outcome compared to major depression without comorbid anxiety disorder. The purpose of our study was to assess changes in severity of both depressive and anxiety symptoms in outpatients with major depression with comorbid anxiety disorder following fluoxetine treatment. We enrolled 123 outpatients (mean age 38.9 ± 10.8 years; 49% women) with major depressive disorder accompanied by one or more current comorbid anxiety disorders in our study. Patients were treated openly with fluoxetine 20 mg/day for 8 weeks. Efficacy assessments included the 17-item Hamilton Rating Scale for Depression (HAM-D) and the patient-rated Symptom Questionnaire (SQ) Scales for Depression and Anxiety. The mood and anxiety disorder modules of the Structured Clinical Interview for DSM-III-R were administered at screen and endpoint. We used ‘intent to-treat’ analysis in examining all patients assigned to treatment and completing the baseline visit. The mean number of comorbid anxiety disorders per patient was 1.5 ± 0.68. The mean HAM-D-17 score and mean Clinical Global Impressions-Severity scores decreased significantly from baseline to endpoint (week 8) following fluoxetine treatment (p < 0.0001). There were significant decreases in all four SQ scale scores, from baseline to endpoint: depression, anxiety, somatic symptoms and anger-hostility (p < 0.0001). Fifty-three percent of patients (n = 65) were depression responders (i.e. ≥ 50% decrease in HAM-D-17 score at endpoint) and 46% (n = 57) were remitters (HAM-D-17 ≤ 7 at endpoint). Patients with panic disorder had significantly higher baseline HAM-D-17 scores compared to those without panic disorder (p< 0.01). Patients with comorbid obsessive–compulsive disorder (OCD) were significantly less likely to be responders to fluoxetine at endpoint (≥ 50% decrease in HAM-D-17) and to be remitters (HAM-D-17 score of ≤ 7 at endpoint) compared to patients without comorbid OCD (p < 0.01). Of the 41 patients on whom endpoint Structured Clinical Interview for DSM-III-R modules for anxiety disorders were available, 49% (n = 20) no longer met criteria for one or more of their anxiety disorder diagnoses at endpoint. Our preliminary findings suggest that fluoxetine is effective in treating outpatients with major depression with comorbid anxiety disorders, with a significant effect on both depression and anxiety symptoms. Further double-blind, placebo-controlled trials are required in larger samples to confirm our findings.