Lifetime prevalence of psychotic and bipolar I disorders in a general population.
BACKGROUND
Recent general population surveys of psychotic disorders have found low lifetime prevalences. However, this may be owing to methodological problems. Few studies have reported the prevalences of all specific psychotic disorders.


OBJECTIVE
To provide reliable estimates of the lifetime prevalences of specific psychotic disorders.


METHODS
General population survey.


METHODS
A nationally representative sample of 8028 persons 30 years or older was screened for psychotic and bipolar I disorders using the Composite International Diagnostic Interview, self-reported diagnoses, medical examination, and national registers. Those selected by the screens were then re-interviewed with the Structured Clinical Interview for DSM-IV. Best-estimate DSM-IV diagnoses were formed by combining the interview and case note data. Register diagnoses were used to estimate the effect of the nonresponders.


METHODS
Diagnosis of any psychotic or bipolar I disorder according to the DSM-IV criteria.


RESULTS
The lifetime prevalence of all psychotic disorders was 3.06% and rose to 3.48% when register diagnoses of the nonresponder group were included. Lifetime prevalences were as follows: 0.87% for schizophrenia, 0.32% for schizoaffective disorder, 0.07% for schizophreniform disorder, 0.18% for delusional disorder, 0.24% for bipolar I disorder, 0.35% for major depressive disorder with psychotic features, 0.42% for substance-induced psychotic disorders, and 0.21% for psychotic disorders due to a general medical condition. The National Hospital Discharge Register was the most reliable of the screens (kappa = 0.80). Case notes supplementing the interviews were essential for specific diagnoses of psychotic disorders.


CONCLUSIONS
Multiple sources of information are essential for accurate estimation of lifetime prevalences of psychotic disorders. The use of comprehensive methods reveals that their lifetime prevalence exceeds 3%.
Perälä
Jonna
J
Department of Mental Health and Alcohol Research, National Public Health Institute, University of Helsinki, Mannerheimintie 166, 0300 Helsinki, Finland. jonna.perala@ktl.fi
Suvisaari
Jaana
J
Saarni
Samuli I
SI
Kuoppasalmi
Kimmo
K
Isometsä
Erkki
E
Pirkola
Sami
S
Partonen
Timo
T
Tuulio-Henriksson
Annamari
A
Hintikka
Jukka
J
Kieseppä
Tuula
T
Härkänen
Tommi
T
Koskinen
Seppo
S
Lönnqvist
Jouko
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology*; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005387:Finland / Q000453:epidemiology; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D015995:Prevalence; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology*; D012042:Registries; D012107:Research Design; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires