Background/aim: Comorbidity of depression in Parkinson disease (PD) is a major factor that changes patients? quality of life. However, the neurobiological and sociodemographic risk factors for this comorbidity are not well studied. In this study, we aimed to define the prevalence, temporal relationship, and psychosocial and clinical determinants of depression comorbid with PD. Materials and methods: Fifty-five PD patients were evaluated with SCID, a data form that assessed sociodemographic and PD-related variables, UPDRS III, HAM-D, HAM-A, MMSE, and the Apathy Evaluation Scale. Results: Depression (lifetime: 45.5%, last month: 25.5%, before PD: 20%) was the most frequent psychiatric diagnosis. The major determinants of depression in the last month and depression before PD were early onset of PD and young age. Patients on pramipexole treatment were less likely to be diagnosed with depression in the last month. Other sociodemographic and PD-related variables were not significantly different for lifetime, last month, and pre-PD depression diagnosis compared to their counterparts. Conclusion: Depression is prevalent both before and after patient gets a PD diagnosis. Depression is not only the result of PD-related life changes but it is also a preceding factor that may decrease the age of PD onset.