The psychiatric complications of Parkinson’s disease (PD) are a source of additional disability and greatly reduce the quality of life of both the patients and the caregivers. Depression, psychosis, impulse control disorders, and other comorbid psychiatric disorders in PD may result from both intrinsic disease-related and iatrogenic treatment-related factors. Functional neuroimaging with PET and SPECT, with tracers for monoamine transmitters, glucose metabolism, and cerebral blood flow, has been used to reveal neuropathophysiological processes underlying specific psychiatric complications of PD. This chapter covers the current knowledge concerning brain PET and SPECT imaging in the psychiatric complications of PD, with a particular focus on the dopaminergic system.