Psychosis and Dementia Commonly Coexist: Hallucinations Are Associated with Depression, and Delusions Are Seen in More Advanced Dementia

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SAN DIEGO -- Delusions and hallucinations are relatively common among people with dementia, according to Dr. Constantine Lyketsos.

Often, they can be managed through a combination of accurate diagnosis, adjustment of precipitating factors, and judicious use of medication, Dr. Lyketsos said at the annual meeting of the Academy of Psychosomatic Medicine.

The incidence of delusions and hallucinations in these patients is 16% and 28%, respectively. Delusions are associated with an increased odds ratio for other symptoms of dementia, such as apathy, depression, and anxiety. Hallucinations are associated primarily with depression, and delusions are usually seen in the more advanced stages of dementia.

The risk of psychotic symptoms in patients with dementia seems higher in brains that turn out on examination to have an imbalance between dopaminergic and cholinergic activity. This leads to a situation Dr. Lyketsos described as "reverse Parkinson's disease," characterized by a relative excess of dopaminergic activity because of the loss of cholinergic nuclei.

Delusions in people with dementia are usually poorly organized but may be persecutory in nature. These patients may experience delusions considered rare in other settings, such as misidentification, or imagining that one's spouse is having an affair.

When hallucinations occur, they're usually visual in nature; auditory hallucinations without a visual component are "almost never seen" in this patient population, said Dr. Lyketsos, professor of psychiatry and codirector of geriatric psychiatry and neuropsychiatry at Johns Hopkins University, Baltimore. This sets them apart from people with schizophrenia, in whom auditory hallucinations are common.

Accurate diagnosis is the first step toward effective management. The Neuropsychiatric Inventory is perhaps the most clinically useful scale for determining if delusions or hallucinations exist. Often, however, patients lack insight into their behavior, so the information must be obtained from a caregiver.

Differential diagnoses include:

* Affective disorders. These may coexist with psychosis and dementia.

* Cognitive disorders such as visual agnosia. The patient may look in the mirror expecting to see a much younger version of herself.

* Visual impairment. …