Presentation of Psychosis
The growing proportion of older adults in the population has increased the interest in psychiatric symptoms and disorders that seriously compromise the quality of life in this age group. Psychotic symptoms are common among both demented and nondemented older adults and demand resources from the social and health care systems. There are different etiologies of these symptoms, and different possible underlying medical contributing illnessess, concomitant medications, dementia, delirium, and psychiatric comorbidities should be identified before a specific antipsychotic treatment is considered.
Key words: psychosis, hallucinations, delusions, paranoid older adults.
Introduction
Studies of nondemented older adults based on interviews show a prevalence of psychotic symptoms, mostly paranoid, of approximately 2%.1,2 The prevalence of psychotic symptoms is possibly underrated because older adults may be reluctant to report those symptoms.1 Thus, it is necessary to collect information from collateral sources (Table 1). One study that has used interview data as well as information from key informants reported a prevalence of 4% among cognitively intact individuals age 70 years and over.3 Another study of nondemented 85-year-olds that used interview data, information from key informants, and medical records reported a 1-year prevalence of psychotic symptoms of 10%.4 Limited data are available about the incidence of psychotic symptoms among older adults. One study of individuals age 70 years and older observed a cumulative incidence rate for psychotic symptoms of 4.8% during 3.6 years in cognitively intact individuals,3 and another found that almost 10% of nondemented 70-year-olds and 20% of those surviving up to age 85 years developed psychotic symptoms for the first time in life during a 20-year follow-up.5
A list of appropriate examinations to perform is presented in Table 2.
Risk Factors for Psychosis
Some risk factors have been associated with the development of psychotic symptoms among older adults. Previous paranoid personality traits have been associated with late-onset psychosis,4,6 and individuals with paranoid symptoms tend to be divorced, lack friends and regular visitors, and be more dependent on community care.3,7
Sensory impairments are common among older adults and have been associated with very-late-onset schizophrenia.8 However, the associations between the type of sensory loss and a specific psychotic symptom are not consistent,4,8,9 not even for Charles Bonnet syndrome, an acute onset of visual hallucinations that usually has been related to eye disease or cerebral organic disorder.10 Hearing impairment has usually been associated with paranoid symptoms, but, again, there are no consistent associations with the type of sensory loss.4,7,11,12 It may be that suboptimal correction of these deficits plays a role in late-life psychotic symptoms.13
Studies of individuals with late-onset schizophrenia have shown its occurrence in a greater number of women than men.8 Population studies on psychotic disorders, however, have generally not found an association with the female sex.14-16 One population-based study on paranoid symptoms reported an association with the female sex,7 whereas two population-based studies on psychotic symptoms found no association.3,4
Impairment, Mortality, and Psychosis
Psychotic symptoms among older adults are associated with cognitive dysfunction. Nondemented older adults with psychotic symptoms perform worse than mentally healthy older adults on cognitive tasks measuring general cognitive abilities--such as verbal ability, logical reasoning, and spatial ability17--and on tests of mental speed.3 Important observations for the differential diagnosis of dementia are that memory test performance is unaffected3,17 and that cognitive deficits are mild. Clinical studies have shown that those with late-onset schizophrenia perform worse than age-matched controls on measures of executive functions, learning, motor skills, and