While treating patients with Parkinson’s disease (PD), clinicians are often confronted with complex clinical pictures, involving cognitive and neuropsychiatric changes in addition to the movement disorder. In fact, patients with PD are susceptible to many neurobehavioral and neuropsychiatric conditions such as neuropsychological disturbances, depression, anxiety, apathy, fatigue, and psychosis. While some of them stem from PD-related neuropathological changes, other disturbances may result from dopaminergic medication (e.g., hallucinations and impulse control disorders). Cognitive changes are frequently seen and may range from mild impairment to overt dementia. Psychiatric conditions often accompany or may even precede motor symptoms. Moreover, neurosurgical interventions, such as deep brain stimulation, may also exert undesired symptoms which have to be considered. Finally, since treatment of behavioral alterations in PD can improve patients overall condition and quality of life and may also result in a reduction of caregiver burden, it is important to recognize these alterations timely, in order to treat them decisively.

This special issue is aimed to update and further expand our understanding of the neurobehavioral symptoms encountered in PD by presenting and discussing actual developments in this multifaceted domain.

Potential topics include but are not limited to the following:

• Epidemiology of neurobehavioral symptoms in PD
• Anxiety, depression, apathy, fatigue, and psychosis in PD
• Neuropsychological disturbances in PD
• MCI and dementia in PD
• Impulse control disorders and pounding in PD
• Neuropsychological testing in PD