A dysfunctional behavior can be defined as “an inappropriate action or response, other than an activity of daily living, in a given social milieu that is a problem for the caregiver.” Dysfunctional behaviors commonly accompany cognitive impairment and are a significant source of burden to caregivers. Dysfunctional behaviors may be the first sign of a dementing illness, even before caregivers perceive changes in the patient's cognitive abilities. However, unlike cognitive impairment, dysfunctional behaviors are amenable to medical treatment. Effective treatment of these behaviors requires their description and identification, evaluation of their frequency and impact on the caregiver, identification of causes, development of a treatment plan, and evaluation of the effects of treatment.