title: Hospitalisation of severely mentally ill patients with and without problematic substance use before and during Assertive Community Treatment: an observational cohort study.
abstract: BACKGROUND
  Co-occurring substance use increases the risk of hospitalisation in people with severe mental illness, whereas Assertive Community Treatment (ACT) generally reduces hospitalisation in patients with severe mental illness and high inpatient service use. Because the superiority of ACT over standard services amongst patients with problematic substance use is uncertain, the present study examined inpatient service use amongst patients with and without problematic substance use in the 2 years before and the 2 years after they enrolled into ACT teams.
  
  
  METHODS
  This naturalistic observational study included 142 patients of 12 different ACT teams throughout Norway. The teams assessed the patients upon enrolment into ACT using clinician-rated and self-reported questionnaires. We obtained hospitalisation data from the Norwegian Patient Register for the 2 years before and the 2 years after enrolment into ACT. We used linear mixed models to assess changes in hospitalisation and to explore associations between problematic substance use and changes in hospitalisation, controlling for socio-demographic and clinical characteristics.
  
  
  RESULTS
  A total of 84 (59%) participants had problematic substance use upon enrolment into the ACT teams. In the 2 years after ACT enrolment both participants with and without problematic substance use experienced a reduction in total inpatient days. Those with problematic substance use also had fewer involuntary inpatient days. Exploratory analyses suggested that symptom severity and functioning level interacted with problematic substance use to influence change in total inpatient days.
  
  
  CONCLUSIONS
  These findings may suggest that ACT teams successfully support people with complex mental health problems in the community, including those with problematic substance use, and thereby contribute to a reduction in inpatient service use.
authors.affiliation: Department of Research & Development, Mental Health Services, Akershus University Hospital, Lørenskog, Norway. hanne.kristin.clausen@ahus.no.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway. hanne.kristin.clausen@ahus.no.
authors.forename: Hanne
authors.initials: H
authors.lastname: Clausen
authors.affiliation: Department of Research & Development, Mental Health Services, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Torleif
authors.initials: T
authors.lastname: Ruud
authors.affiliation: National Centre for Dual Diagnosis, Innlandet Hospital Trust, Brumunddal, Norway.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Odden
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|HØKH Research Centre, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Jūratė
authors.initials: J
authors.lastname: Šaltytė Benth
authors.affiliation: Department of Research & Development, Mental Health Services, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Kristin Sverdvik
authors.initials: KS
authors.lastname: Heiervang
authors.affiliation: National Centre for Dual Diagnosis, Innlandet Hospital Trust, Brumunddal, Norway.
authors.forename: Hanne Kilen
authors.initials: HK
authors.lastname: Stuen
authors.affiliation: Division of Psychiatry, University College London, London, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Killaspy
authors.affiliation: Dartmouth Psychiatric Research Center, Lebanon, New Hampshire, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Drake
authors.affiliation: National Centre for Dual Diagnosis, Innlandet Hospital Trust, Brumunddal, Norway.|Addiction Research, University of Oslo, Oslo, Norway.
authors.forename: Anne
authors.initials: A
authors.lastname: Landheim
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003156:Community Mental Health Services / Q000458:organization & administration; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D028642:Persons with Psychiatric Disorders / Q000523:psychology* / Q000706:statistics & numerical data; D008875:Middle Aged; D009664:Norway; D057566:Self Report; D019966:Substance-Related Disorders / Q000523:psychology* / Q000628:therapy*; D011795:Surveys and Questionnaires
keywords: Assertive community treatment; Hospitalisation; Inpatient care; Problematic substance use