To identify the occurrence of serotonin toxicity in Parkinson's Disease (PD) patients receiving antidepressant therapy and rasagiline, compared to those receiving rasagiline without antidepressant medications and compared to PD patients receiving antidepressants, but not rasagiline.

Inclusion Criteria:

1. Male or female patients with a diagnosis of PD

2. Rasagiline treatment as mono- or adjunct therapy for PD with concomitant antidepressant medication (SSRIs, SNRIs, St. John's wort and/or TCAs) at any time during the specified review period, OR Rasagiline treatment as mono- or adjunct therapy for PD without concomitant antidepressant medication (SSRIs, SNRIs, St. John's wort and/or TCAs) at any time during the specified review period. OR Antidepressant therapy (SSRIs, SNRIs, St. John's wort and/or TCAs) and any other dopaminergic anti-PD treatment besides rasagiline or selegiline at any time during the specified review period

3. Willing to consent to review of office chart and to review of records of ER visits and/or hospitalizations corresponding to the review window, if required

4. Patients previously participating in a rasagiline clinical trial (and their follow-up protocols) are eligible, provided that they did not receive antidepressant therapy during trial participation.

5. In addition to the above criteria, each group has specific inclusion criteria stated below:

   • Group R+AD: Enrollment in this group requires that patients must have taken rasagiline and an antidepressant (SSRIs, SNRIs, St. John's wort and/or TCAs, regardless of indication) within 14 days of each other (or five weeks, if fluoxetine preceded rasagiline).
   • Group R: Enrollment in this group requires patients must have at least 2 months of rasagiline use.
   • Group AD: Patients must be taking an approved dopaminergic medication for PD. Enrollment in this group requires that patients must have at least 2 months of treatment with an antidepressant medication.

Exclusion Criteria:

1. Use of rasagiline for any indication other than PD
2. Patients taking a monoamine oxidase inhibitor (MAOI) antidepressant and/or selegiline
3. Inability or unwillingness to request records of ER visits and/or hospitalizations corresponding to the review period.

Male or female patients with a diagnosis of PD:

• who received rasagiline at any dose, as mono- or adjunct therapy for PD, with concomitant antidepressant medication, OR
• who received rasagiline at any dose, as mono- or adjunct therapy for PD, without concomitant antidepressant medication, OR
• who received antidepressant medication and any other dopaminergic anti-PD therapy besides rasagiline or selegiline including dopaminergic agents, anticholinergics, amantadine, deep brain stimulation (DBS), pallidotomy, etc.