Introduction: Behavioral disturbances in patients with Alzheimer's disease (AD) are ill-defined conditions. We hypothesize that the many behavioral disturbances hitherto described and studied might be grouped into few syndromes with separate determinants and correlates.
Patients and methods: 162 consecutive patients with probable AD admitted to a dementia unit were assessed by the UCLA Neuropsychiatric Inventory (NPI).
Results: Factor analysis was carried out on NPI subscales, leading to three syndromes: 'mood', 'psychotic' and 'frontal'. Patients with the 'psychotic' syndrome were older, had older age at dementia onset, had poorer cognition, were more often males, and had faster rate of dementia progression. Patients with the 'frontal' syndrome had higher education, longer disease duration, and slower rate of progression.
Discussion: Some combinations of behavioral disturbances occur more frequently together and might represent separate behavioral syndromes. Different clinical correlates of the syndromes suggest separate etiologies.