title: Association between depression and non-fatal overdoses among drug users: a systematic review and meta-analysis.
abstract: BACKGROUND
  Assessing factors associated with non-fatal overdose is important as these could be useful to identify individuals with substance use disorders at high risk of adverse outcomes and consequences. Depression may play an important role in terms of overdose risk. We aimed to test if drug users suffering from a depressive disorder might have significantly higher risk of non-fatal overdose as compared with drug users without depression.
  
  
  METHODS
  We conducted a systematic review and meta-analysis. PubMed, Embase and Web of Knowledge were searched. The pooled analyses were based on prevalence rates, risk difference (RD) and odds ratio (OR), reporting 95% confidence intervals (CIs). The combined estimates were obtained weighting each study according to random effects model for meta-analysis.
  
  
  RESULTS
  Seven articles, involving 12,019 individuals, and run in the US, Canada, Sweden, Norway, and Australia, were included. Pooled analyses comparing depressed with not depressed individuals highlighted a RD (95% CIs) for non-fatal overdose of 7.3% (4.8-9.7%) and an OR (95% CIs) of 1.45 (1.17-1.79). The subgroups analyses based on specific characteristics of included studies confirmed the association between depression and overdose.
  
  
  CONCLUSIONS
  Depressive disorders seem to be important factors associated to the risk of non-fatal overdose. Longitudinal studies might appropriately clarify causal inference issues. Future research should address the role of depressive disorders as predictors of subsequent non-fatal overdoses.
authors.affiliation: Department of Surgery and Interdisciplinary Medicine, University of Milano Bicocca, Milano 20126, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bartoli
authors.affiliation: Mental Health Sciences Unit, Faculty of Brain Sciences, University College London, W1W 7EJ, UK. Electronic address: g.carra@ucl.ac.uk.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Carrà
authors.affiliation: Department of Surgery and Interdisciplinary Medicine, University of Milano Bicocca, Milano 20126, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Brambilla
authors.affiliation: Department of Surgery and Interdisciplinary Medicine, University of Milano Bicocca, Milano 20126, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Carretta
authors.affiliation: Department of Mental Health, San Gerardo Hospital, Monza 20900, MB, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Crocamo
authors.affiliation: Medical and Biological Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9TF, UK.
authors.forename: Julia
authors.initials: J
authors.lastname: Neufeind
authors.affiliation: Division of Neuroscience, Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Baldacchino
authors.affiliation: Medical and Biological Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9TF, UK.
authors.forename: Gerry
authors.initials: G
authors.lastname: Humphris
authors.affiliation: Department of Surgery and Interdisciplinary Medicine, University of Milano Bicocca, Milano 20126, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Clerici
mesh_terms: D003863:Depression / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D062787:Drug Overdose / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D055030:Drug Users / Q000523:psychology*; D006801:Humans; D019966:Substance-Related Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology
keywords: Depression; Drug overdose; Meta-analysis