The course of behavioural and psychotic features of patients with Alzheimer's disease treated with an inhibitor of the acetylcholinesterase (rivastigmine), and their association to cognitive impairment is presented in the study. Standardized examination of global functional deterioration (GDS), cognitive impairment (MMSE) and behavioural or psychotic symptoms (Behave-AD) were performed over two years. We could analyse the complete data from 44 of initially 91 patients with mild to moderate Alzheimer's disease. The cognitive component (measured by MMSE, ADAS-cog) and the functional assessment (GDS) showed a continuous decline after a one year period of stabilization, in contrast with behavioural and psychotic symptoms, especially delusions, which still improved after treatment of two years. While cognitive items in correlation with functional aspects formed a homogeneous factor over the two-year period, psychotic features displayed more variability over time evaluated by factor analysis. Nevertheless mood and anxiety disorder in combination with aggressive behaviour as well as hallucinations formed an independent factor in the course of Alzheimer's disease. In addition to other studies of the course of Alzheimer's disease we could demonstrate that distinct behavioural and psychotic symptoms may also present as independent factors in Alzheimer patients under constant treatment conditions with an inhibitor of the acetylcholinesterase (rivastigmine).