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.