Up to 90% of patients with Parkinson’s disease (PD) experience neuropsychiatric symptoms (NPSs) including depression, anxiety, psychosis, impulse control disorders, and cognitive impairment. NPSs impact a patient’s quality of life and are more delicate and distressing than the motor aspects of PD. Treatment options include pharmacological and non-pharmacological interventions such as deep brain stimulation (DBS), repetitive transcranial magnetic stimulation (rTMS), and electroconvulsive therapy (ECT). Depression is the most common NPS in PD, with mild to moderate depressive symptom severity and impairments in the subcortical nuclei, prefrontal cortex, and monoamine systems. Depression in PD (DPD) may precede the onset of motor symptoms by years or even decades, leading to poor cognitive performance, worse functional status, and an increased risk of death. It is essential to diagnose and treat DPD early in patients. Cognitive behavioral therapy (CBT) is recommended for DPD psychotherapy. Common clinical depression scales are recommended for assessments of the severity of depressive symptoms in PD. The treatment decision-making process must consider both the potential benefit and adverse effects in PD and NPS.