Agitation often accompanies dementia and often precedes the diagnosis of common age-related disorders of cognition such as Alzheimer's disease (AD). More than 80% of people who develop AD eventually become agitated or aggressive.
It is important to rule out infection and other environmental causes of agitation, such as disease or other bodily discomfort, before initiating any intervention. If no such explanation is found, it is important to support caregivers and educate them about simple strategies such as distraction that may delay the transfer to institutional care (which is often triggered by the onset of agitation). 
There is no FDA-approved treatment for agitation in dementia.
Medical treatment may begin with a cholinesterase inhibitor, which appears safer than other alternatives although evidence for its efficacy is mixed. If this does not improve the symptoms, atypical antipsychotics may offer an alternative, although they are effective against agitation only in the short-term while posing a well-documented risk of cerebrovascular events (e.g. stroke). Other possible interventions, such as traditional antipsychotics or antidepressants, are less well studied for this condition. 
- Jost BC, Grossberg GT (1996). "The evolution of psychiatric symptoms in Alzheimer's disease: a natural history study". J Am Geriatr Soc. 44 (20): 1078–1081. PMID 8790235.
- Mittelman MS, Haley WE, Clay OJ, et al. (2006). "Improving caregiver well-being delays nursing home placement of patients with Alzheimer disease". Neurology. 67 (9): 1592–1599. doi:10.1212/01.wnl.0000242727.81172.91. PMID 17101889.
- James M. Ellison (February 1, 2008). "Agitation in dementia: Update and prospectus". Psychiatric Times. 25 (2).