title: Changing incidence of psychotic disorders among the young in Zurich.
abstract: There is controversy over whether the incidence rates of schizophrenia and psychotic disorders have changed in recent decades. To detect deviations from trends in incidence, we analysed admission data of patients with an ICD-8/9/10 diagnosis of psychotic disorders in the Canton Zurich / Switzerland, for the period 1977-2005. The data was derived from the central psychiatric register of the Canton Zurich. Ex-post forecasting with ARIMA (Autoregressive Integrated Moving Average) models was used to assess departures from existing trends. In addition, age-period-cohort analysis was applied to determine hidden birth cohort effects. First admission rates of patients with psychotic disorders were constant in men and showed a downward trend in women. However, the rates in the youngest age groups showed a strong increase in the second half of the 1990's. The trend reversal among the youngest age groups coincides with the increased use of cannabis among young Swiss in the 1990's.
authors.affiliation: Research Unit for Clinical and Social Psychiatry, Psychiatric University Hospital, Zurich, Switzerland. vajdacic@spd.unizh.ch
authors.forename: Vladeta
authors.initials: V
authors.lastname: Ajdacic-Gross
authors.forename: Christoph
authors.initials: C
authors.lastname: Lauber
authors.forename: Inge
authors.initials: I
authors.lastname: Warnke
authors.forename: Helene
authors.initials: H
authors.lastname: Haker
authors.forename: Robin M
authors.initials: RM
authors.lastname: Murray
authors.forename: Wulf
authors.initials: W
authors.lastname: Rössler
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D005544:Forecasting; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D015994:Incidence; D038801:International Classification of Diseases / Q000706:statistics & numerical data; D008297:Male; D002189:Marijuana Abuse / Q000175:diagnosis / Q000453:epidemiology; D015233:Models, Statistical; D010343:Patient Admission / Q000639:trends; D000297:Psychology, Adolescent; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology*; D012042:Registries / Q000706:statistics & numerical data; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D017678:Sex Distribution; D012737:Sex Factors; D013557:Switzerland / Q000453:epidemiology