To assess the predictive value of sequential administration of WHO-5 and MDI (Major Depression Inventory) for the clinical management of Parkinson Disease (PD) patients by

• determination of the prevalence of depression in PD patients, based on MDI severity categories and the self-rating scale WHO-5, where poor well being was indicated.
• exploration of influencing factors (PD status, therapeutic status) on the prevalence of MDI depression categories.

Inclusion Criteria:

1. PD patients attending one of the participating neurologist practices during 2 fixed weeks in November 2008
2. Idiopathic PD with or without fluctuations
3. Male or female PD patients aged at least 30
4. Ability to reliably complete self-rating scales (WHO-5, MDI) ), according to the physician's judgement.
5. Written informed consent by the patient for study participation.

Exclusion Criteria:

1. PD Patients who only attend the practice to get a prescription and are not seen by the doctor on that day
2. Patients who are not able to understand the questionnaires (e.g. due to mental impairment or language problems).

resident physician