Objectives: Psychiatric disorders in patients with Parkinson’s disease (PD) and their caregivers play an important role in patients’ treatment and follow-up. Our study aimed to examine the prevalence of psychiatric symptoms among patients with PD and their caregivers, demographic risk factors, and the influence of severity and manifestations of PD on psychiatric distress. Methods: We included 125 patients with PD and 125 of their primary caregivers in this descriptive cross-sectional study. The severity of PD was evaluated according to the Hoehn and Yahr severity scale from the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale. PD patients and their caregivers completed the Symptom Checklist-25 to determine the presence of psychiatric distress. Also, demographic factors, including age, high level of education, occupation, residence, and cigarette smoking, were assessed in the PD patients and their caregivers. Results: The prevalence of psychiatric distress was 47.2% for PD patients and 18.4% for caregivers. Female sex, city residency, and medical disease were risk factors for more psychiatric symptoms in PD patients. Also, the female sex, single status, living in a village, and having a medical disease were risk factors for greater psychiatric symptoms in caregivers. PD patients in more advanced stages of disease suffered significantly from psychiatric distress, somatization, anxiety, interpersonal sensitivity, obsessive-compulsive disorder, and phobia compared to the lower severity of disease. PD patients with manifestation of postural instability showed a higher score of somatization, phobia, and psychiatric distress as compared with tremor, hypokinesia, and rigidity. Conclusions: Progression of PD influenced the psychiatric symptoms of both patients and their caregivers. A higher stage of PD is associated with higher scores of psychiatric distress, phobia, and somatization in the patients and their caregivers.