First-episode schizophrenia, bipolar disorder and other psychoses in a rural Irish catchment area: incidence and gender in the Cavan-Monaghan study at 5 years.
BACKGROUND
The potential of first-episode studies in schizophrenia is maximised through systematic epidemiological, clinical and biological comparisons between homogeneous populations of the psychoses.


OBJECTIVE
To conduct prolonged accrual of 'all' cases of non-affective and affective psychotic illness on an epidemiologically complete basis.


METHODS
Within the region covered by Cavan-Monaghan psychiatric service (population 102,810), all putative cases of first-episode psychosis were diagnosed using DSM-IV.


RESULTS
From 1995 to 2000, 69 cases of psychosis were ascertained, the incidence being 2.3-fold lower in females than in males. On resolving the 'core' diagnoses of schizophrenia and bipolar disorder, incidence of schizophrenia among women was 7.5-fold lower than among men whereas incidence of bipolar disorder among women was 6.6-fold lower than among men.


CONCLUSIONS
This homogeneous population, which eliminates factors associated with urbanicity and minimises confounding factors such as socioeconomic, ethnic and geographical diversity, shows a markedly reduced incidence among females both of schizophrenia and of bipolar disorder.
Scully
Paul J
PJ
Stanley Research Unit, St Davnet's Hospital, Monaghan, Ireland.
Quinn
John F
JF
Morgan
Maria G
MG
Kinsella
Anthony
A
O'Callaghan
Eadbhard
E
Owens
John M
JM
Waddington
John L
JL
D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology; D002391:Catchment Area, Health; D005260:Female; D006801:Humans; D015994:Incidence; D007494:Ireland / Q000453:epidemiology; D008297:Male; D008605:Mental Health Services / Q000458:organization & administration; D011446:Prospective Studies; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology*; D012423:Rural Health / Q000706:statistics & numerical data; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D012737:Sex Factors