Advances in the assessment of the behavioral and psychological symptoms of dementia (BPSD) have been employed in large-scale clinical trials of new antipsychotic medications such as risperidone. These scales can be used to assess drug efficacy and to compare different treatment regimens. We review 3 valid and reliable scales, the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD), the Cohen-Mansfield Agitation Inventory (CMAI), and the Neuropsychiatric Inventory (NPI). Extrapyramidal side effects (EPS) associated with the treatment of BPSD have also been assessed using a number of rating instruments. The design of the most comprehensive of these, the Extrapyramidal Symptom Rating Scale (ESRS), is exhaustive, and it successfully quantifies EPS and distinguishes toxic from nontoxic medications. This publication serves as an aid to researchers and clinicians in their interpretation of qualitative and quantitative data from trials evaluating antipsychotic agents in the treatment of BPSD.