Objective: This study aimed to investigate the presence of psychiatric symptoms in patients with Parkinson’s disease through validated psychiatric scales and assessments, and to evaluate the relationship between these symptoms and disease severity. Method: The study was conducted at the neurology outpatient clinic of Haydarpasa Numune Training and Research Hospital patients diagnosed with idiopathic Parkinson’s disease.An age and sex matched healthy control group was also recruited. Individuals with prominent motor fluctuations, psychosis, or dementia were excluded. Participants underwent assessments using the Maudsley Obsessive-Compulsive Inventory (MOCI), Barratt Impulsiveness Scale (BIS), Apathy Evaluation Scale (AES), Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s Disease (QUIP), Non-Motor Symptoms Questionnaire (NMSQ), and the Unified Parkinson’s Disease Rating Scale (UPDRS) to evaluate clinical functionality specific to Parkinson’s disease. Results: An increase in obsessive compulsive symptom severity was found to be positively correlated with UPDRS scores and impulsivity levels. The patient group exhibited significantly higher levels of apathy and impulsivity compared to the control group. Conclusion: Our data revealed significant associations between disease severity and symptoms of apathy, obsessive-compulsive behaviors, and impulsivity. Our results also suggest that obsessive-compulsive symptoms may act as risk factors for increased non-motor symptom burden. Apathy scores were significantly higher in the patient group compared to controls, supporting these findings in the literature. Psychiatric manifestations significantly impact the clinical course and quality of life in Parkinson’s disease. Regular evaluation of these symptoms using standardized psychiatric scales is strongly recommended for comprehensive patient care.