Schizophrenia risk factors constitute general risk factors for psychiatric symptoms in the population.
BACKGROUND
The presence of a psychosis continuum is suggested by studies showing that schizophrenia and non-clinical psychotic symptoms in the general population share the same risk factors. However, to our knowledge no large-scale studies have been conducted which examine the specificity of these risk factors in the general population.


OBJECTIVE
To investigate whether socio-demographic characteristics associated with non-clinical psychotic symptoms are also associated with other psychiatric symptoms. And secondly, to examine to what extent concomitant psychiatric symptoms explain the relationship between socio-demographic characteristics and non-clinical psychotic symptoms.


METHODS
In a general population sample of 4894 subjects (mean age 39 years, 45% men) from the Utrecht Health Project we investigated the associations of socio-demographical characteristics with non-clinical psychotic symptoms and other psychiatric symptoms by using the SCL-90. We examined these associations using multivariable logistic regression analyses with and without controlling for the presence of other psychiatric symptoms.


RESULTS
Participants with non-clinical psychotic symptoms had an 89% probability of concomitant depressive, anxiety or phobic anxiety symptoms, compared to 11% in participants without psychotic symptoms. The risk profiles for non-clinical psychotic symptoms and other psychiatric symptoms were largely similar. Non-Dutch ethnicity was most strongly associated with non-clinical psychotic symptoms. Adjusting for other psychiatric symptoms did not increase the specificity of the risk factors.


CONCLUSIONS
Socio-demographic risk factors for non-clinical psychotic symptoms in the general population are also risk factors for other psychiatric symptoms. The relationship between these risk factors and psychotic symptoms are for a substantial part explained by an increase in other psychiatric symptoms.
Breetvelt
Elemi J
EJ
Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands. E.J.Breetvelt@umcutrecht.nl
Boks
Marco P M
MP
Numans
Mattijs E
ME
Selten
Jean-Paul
JP
Sommer
Iris E C
IE
Grobbee
Diederick E
DE
Kahn
René S
RS
Geerlings
Mirjam I
MI
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology* / Q000503:physiopathology*; D008875:Middle Aged; D016017:Odds Ratio; D044382:Population Groups; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult