This review of instruments for the identification and quantification of psychiatric symptoms in Alzheimer disease (AD) is intended as a reference source for clinicians and researchers concerned with evaluating, quantifying, and managing psychiatric symptoms in AD. We review 16 clinician- and caregiver-rated scales selected from >30 scales on the basis of their face validity, their psychometric properties, the frequency of their use, and their promise as assessment instruments. Instruments are described in terms of the population on which they were developed, the symptoms assessed, informant, by whom administered, time to administer, time interval covered, number of items, measurement of frequency and severity, assessment of impact on caregiver, reliability, validity, and scoring. Recommendations are made concerning the best use of each scale. We summarize in table form the sources of information for instruments, characteristics of the instruments by domain, and potential use of instruments for quantification or management of symptoms and for estimation of caregiver burden. There are a number of reliable and valid scales for the assessment of psychiatric symptoms in AD, each with specific assets and liabilities. Knowledge of the specifics of these scales will enable clinicians and researchers to select the best instruments for their particular needs and to design more effective instruments.