Huntington's disease (HD) is an autosomal, dominant, inherited disorder of the central nervous system with characteristic neurodegenerative alterations in the basal ganglia and cortex. Dependent on the individual CAG expansion load, disease onset occurs between the third or fourth decade of life, entailing an invariably lethal progression within 10 to 20 years. Although the clinical picture is characterized equally by cognitive and psychiatric disturbances, the apparent neurodegenerative alterations and presentation as a choreatic movement disorder account for the traditional link of Huntington's disease to the field of neurology. In contrast to the traditionally emphasized core features of chorea and dementia, recent empirical evidence points to the frequent emergence of nonchoreatic motor signs and subtle cognitive and psychiatric complaints, especially in asymptomatic gene carriers and early disease stages. The case studies presented here emphasize the spectrum of neuropsychiatric phenomena associated with HD and illustrate the resulting difficulties of differential diagnosis in clinical settings. Furthermore, current scientific knowledge of HD pleiotrophy is reviewed and the diagnostic power of specific neuropsychological approaches is explained.