The main goal of treatment in patients with Panic Disorder (PD) is to effect a rapid reduction in symptom severity and improve functioning. While numerous pharmacological approaches have been used to treat PD, these treatments are limited by variable response rates, up to a 6-week lag period prior to the onset of clinical response, and sub-optimal side effect profile, including possible worsening of anxiety and insomnia.~There is recent evidence that the benzodiazepine clonazepam prescribed with selective serotonin reuptake inhibitors (SSRI) can facilitate a rapid reduction of symptoms in PD. The improvement in symptoms was maintained despite tapering the clonazepam prior to the end of the study. However, it was unclear if co-morbid depression influenced the treatment response to this regimen. In addition, a recent study in patients with major depression demonstrated that combined fluoxetine-clonazepam treatment resulted in a more rapid antidepressant response than the fluoxetine-placebo combination.~The proposed study will examine whether combined treatment with a clonazepam and paroxetine in patients with PD and comorbid depression will accelerate the onset of clinical response at both panic and depression symptoms. PD with comorbid major depression is a more severe disorder than PD alone. We will also examine whether the rapid and clinically meaningful benefits will be sustained until the end of the study, despite tapering off clonazepam at the midpoint of the study. If this study turns out to be the case combined SSRI-benzodiazepine treatment may become a standard initial therapeutic approach to PD and comorbid major depression.
The purpose of this study is to examine the safety and effectiveness of the drug combination paroxetine and clonazepam in treating people with panic disorder (PD) and major depression.~The main goal in treating people with PD is to rapidly reduce symptom severity and improve functioning. While numerous drug therapies have been used to treat PD, these treatments are limited by variable response rates and suboptimal side effect profiles. Evidence suggests that clonazepam given with a selective serotonin reuptake inhibitor (SSRI) can facilitate a rapid reduction in PD symptoms. However, it is unclear whether comorbid depression influences treatment response to the clonazepam and SSRI regimen. This study will examine whether combined treatment with clonazepam and the SSRI paroxetine will accelerate clinical response in participants with PD and comorbid depression. This study will also examine whether the benefits of treatment will be sustained until the end of the study despite tapering of clonazepam at the midpoint of the study.~Participants in this study will be screened with medical and psychiatric interviews, a physical examination, electrocardiogram (ECG), and blood tests. Participants will then be randomly assigned to receive either paroxetine plus clonazepam or paroxetine plus placebo (an inactive pill) for 12 weeks. Participants will have weekly clinic visits during which symptoms and drug side effects will be checked and an interview to evaluate panic disorder and depression symptoms will be conducted.