Psychotic symptoms in older people without dementia from a Brazilian community-based sample: A seven years' follow-up.

BACKGROUND

Studies of the incidence of psychotic symptoms in elderly people at risk of dementia are scarce. This is a seven year follow up study aiming to determine the incidence of psychotic symptoms and their correlation with other clinical aspects, in particular the rate of development of cognitive impairment.

METHODS

Cohort study of a community-based sample of elderly subjects. At study entry in 2004, the sample was composed of 1,125 individuals aged 60 years and older. Of this total, 547 subjects were re-evaluated in 2011 and submitted to the original study protocol. Of these, 199 showed no psychotic symptoms at phase I, while 64 already had psychotic symptoms in 2004.

RESULTS

The incidence of at least one psychotic symptom in the 7 year period was 8.0% (Visual/tactile hallucinations: 4.5%; Persecutory delusions: 3.0%; Auditory hallucinations: 2.5%). Development of psychotic symptoms was associated with epilepsy (OR: 7.75 and 15.83), lower MMSE (OR: 0.72) and reported depression (OR: 6.48). A total of 57.8% of individuals with psychotic symptoms developed cognitive impairment after 7 years. Visual/tactile hallucinations were the only psychotic symptom predictive of this impairment, which was related to lower MMSE and greater functional impairment.

CONCLUSIONS

The incidence of psychotic symptoms and the conversion rate to cognitive impairment was in the upper range when compared with previous reports. Visual/tactile hallucinations were the most frequent symptoms and were predictive of cognitive impairment over the 7 year period. A significant relationship was found between the incidence of psychotic symptoms and low MMSE scores, as well as clinical comorbities such as epilepsy, reported depression, diabetes and syphilis.