This chapter reviews the principles of pharmacotherapy for neuropsychiatric disturbances and addresses practical issues that often arise during treatment. There are controlled clinical trials assessing the effects of medications on neuropsychiatric symptoms among neurodegenerative dementias. Side effect profiles may guide medication selection, especially when selecting among several medications within a particular pharmacologic class. An individual clinician's prior experience with the use of a particular medication to treat a specific neuropsychiatric problem also influences treatment selection. Continuous reassessment of treatment need is necessary whenever medications are prescribed. Vigilant observation for the development of drug-drug interactions is necessary. These interactions may be predicated on medication combination-specific alteration of pharmacokinetics that result in increased half-lives and serum levels of medications. In Behavioral Neurology & Neuropsychiatry (BN&NP), many medications are used for non-approved indications. While physicians are permitted to prescribe medications for non-approved purposes, insurance carriers may not approve payment for such prescriptions.