Apathy in Parkinson's disease

Abstract

Apathy is a common word used to describe an inner lack of motivation that is distinct from a depressive condition, cognitive impairment, fatigue, or emotional sorrow. Apathy can be an isolated syndrome or a prominent feature found in depression and post-injury events such as stroke or trauma, infectious or metabolic comorbidities in neurodegenerative conditions (e.g., dementias, movement disorders), schizophrenia, and other systemic illness. Because of these, despite its estimated high prevalence, misdiagnosis of apathy as a syndrome is frequent and probably underestimated. Because apathetic patients, by definition, are non-complainers, Parkinson's disease (PD) patients will often first acknowledge the presence of motor impairment, and even other behavioral symptoms, cognitive compromise, and worsening of quality of life before complaining of lack of motivation or loss of interest. The differentiation between apathy, fatigue, and depression also can become a challenge due to the overlap of symptoms.