Psychosis risk as a function of age at onset: a comparison between early- and late-onset psychosis in a general population sample.
BACKGROUND
Little is known about late-onset psychosis (onset after the age 45 years) and how it relates to early-onset psychosis (before age 45 years). The aims of this study were to calculate the incidence of non-affective, non-organic psychotic symptoms across the life span and to explore the contribution of different sets of risk factors in relation to age at onset.


METHODS
Data were obtained from the three measurements of the Netherlands Mental Health Survey and Incidence Study. Symptoms of psychosis were assessed in individuals aged 18-64 years using the Composite International Diagnostic Interview. All individuals reporting first-onset of psychotic symptoms within a three-year interval were included. The degree to which sets of risk factors affected the psychosis outcome similarly across age groups was assessed.


RESULTS
The number of subjects displaying incident psychotic symptoms was similar across age groups. Cumulative incidence rates ranged from 0.3% to 0.4%. Age differences were found for life-time depressive symptoms (risk difference = 5%, 95% CI = 1%, 9%) and baseline neuroticism (risk difference = 3%, 95% CI = 0%, 6%), indicating that late-onset psychosis was less often preceded by these. In contrast, no effect modification by age was observed for female sex, hearing impairment, being single, or life-time cannabis use.


CONCLUSIONS
Onset of psychotic symptoms in late life is no rare event. Compared to early onset psychosis, the late-onset counterpart less often arises in a context of emotional dysfunction and negative affectivity, suggesting qualitative differences in aetiology and more effective premorbid coping styles.
Köhler
Sebastian
S
Department of Psychiatry and Neuropsychology, Sth Limburg Mental Health Research and Teaching Network, EURON, Maastricht University, P.O. Box 616 (VIJV), 6200, MD, Maastricht, The Netherlands.
van Os
Jim
J
de Graaf
Ron
R
Vollebergh
Wilma
W
Verhey
Frans
F
Krabbendam
Lydia
L
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D011618:Psychotic Disorders / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology*; D012307:Risk Factors; D012720:Severity of Illness Index