The impact of neuropsychiatric symptoms on quality of life in Parkinson’s disease

Parkinson's disease (PD) is a progressive disorder presenting with motor and non-motor symptoms (NMS) and significant deterioration in quality of life over the years. We will refer in this chapter specifically to health-related quality of life (HRQoL), a construct more restricted than the global quality of life. HRQoL is a multidimensional concept including those aspects of the quality of life depending on or related to health status, and may be defined as “the perception and evaluation by patients themselves of the impact caused on their lives by the disease and its consequences” [1]. In this way, HRQoL adds to the self-assessment of perceived health (in physical, emotional, functioning, and social aspects), judgments and reflections about well-being, and satisfaction with health, involving a combination of objective functioning and subjective perceptions of health. HRQoL determinants show a consistent and constant relationship with HRQoL status, which they influence directly. Identification of determinants causing HRQoL deterioration is important, because if they can be neutralized or alleviated a subsequent improvement in a patient’s HRQoL may be expected. Associated factors, however, do not have a close and stable relationship with HRQoL, and modifying them might not lead to change in HRQoL.