A review of agitation in mental illness: burden of illness and underlying pathology.

Agitation has been poorly addressed as a unique entity in many psychiatric disorders. Recent medical literature and a range of instruments have measured agitation in various clinical settings. Agitation is a common problem in many patients with schizophrenia, bipolar mania, or dementia. Moreover, agitation adversely impacts many facets of the healing process, including direct patient care, caregiver burden, and community resources. Frontal lobe dysfunction and mutations in the catechol O-methyltransferase (COMT) gene involved in dopamine metabolism and catecholamine inactivation have been linked to agitation in patients with schizophrenia and bipolar disorder. Cerebral impairment and deficits in cognitive function predispose patients with dementia to agitation. In patients with Alzheimer's dementia, both frontal and temporal lobe pathology may be associated with agitation. Addressing agitation as a symptom of psychiatric illness would represent a great opportunity for therapeutic intervention and the alleviation of patient suffering, family burden, and societal costs.