title: Treated incidence and baseline characteristics of substance induced psychosis in a Norwegian catchment area.
abstract: BACKGROUND
  Substance misuse is a well-recognized co-morbidity to psychosis and has been linked to poor prognostic outcomes in patients. Researchers have yet to investigate the difference in rates and characteristics between first-episode Substance Induced Psychosis (SIP) and primary psychosis. We aimed at comparing patients with SIP to primary psychosis patients with or without substance misuse at baseline.
  
  
  METHODS
  Thirty SIP patients, 45 primary psychosis patients with substance misuse (PS) and 66 primary psychosis patients without substance misuse (PNS) in a well-defined Norwegian catchment area were included from 2007-2011. Assessments included symptom levels (PANSS), diagnostic interviews (SCID), premorbid function scale (PAS) and global functioning (GAF f/s).
  
  
  RESULTS
  Treated incidence for SIP was found to be 6.5/100 000 persons per year, 9.7/100 000 persons per year for PS and 24.1/100 000 persons per year for PNS (15-65 yrs). Patients who had substance misuse (PS and SIP) were more likely to be male. Duration of Untreated Psychosis (DUP) was significantly shorter in the SIP group (5.0 wks., p = 0.003) and these had more positive symptoms on the PANSS (p = 0.049). SIP patients also did poorer on early youth academic levels on the PAS.
  
  
  CONCLUSIONS
  Yearly treated incidence of SIP is 6.5/100 000 persons per year in a Norwegian catchment area. SIP patients have short DUPs, are more likely to be male, have more positive symptoms at baseline and poorer premorbid academic scores in early adolescence. Follow-up will evaluate stability of diagnosis and characteristics.
authors.affiliation: Regional Centre for Clinical Research in Psychosis, TIPS, Stavanger University Hospital, Armauer Hansensvei, 4014 Stavanger, Norway. weim@sus.no.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Weibell
authors.forename: Inge
authors.initials: I
authors.lastname: Joa
authors.forename: Jørgen
authors.initials: J
authors.lastname: Bramness
authors.forename: Jan Olav
authors.initials: JO
authors.lastname: Johannessen
authors.forename: Patrick D
authors.initials: PD
authors.lastname: McGorry
authors.forename: Wenche
authors.initials: W
authors.lastname: Ten Velden Hegelstad
authors.forename: Tor Ketil
authors.initials: TK
authors.lastname: Larsen
mesh_terms: D000293:Adolescent; D000328:Adult; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011605:Psychoses, Substance-Induced / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology*; D019966:Substance-Related Disorders / Q000175:diagnosis / Q000453:epidemiology*