Occup Environ Med doi:10.1136/oemed-2011-100182
  • Workplace
  • Original article

Business mergers and acquisitions and the risk of mental disorders: a population-based study

  1. Norbert Schmitz5
  1. 1Department of Psychiatry, Faculty of Medicine, University of Calgary, Calgary, Canada
  2. 2Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Calgary, Canada
  3. 3Mental Health and Addiction Program, Mental Health Information and Evaluation, Alberta Health Services, Calgary, Canada
  4. 4Department of Psychiatry, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
  5. 5Department of Psychiatry, Faculty of Medicine, McGill University, Montreal, Canada
  1. Correspondence to Dr JianLi Wang, Department of Psychiatry, Faculty of Medicine, University of Calgary, Room 4D69, TRW Building, 3280 Hospital Dr NW, Calgary, AB, Canada T2N 4Z6; jlwang{at}
  1. Contributors All authors were involved in design, results interpretation and final approval of the manuscript. JLW conducted statistical analysis and prepared the first draft.

  • Accepted 20 November 2011
  • Published Online First 6 January 2012


Objectives Mergers and acquisitions (M&A) activities are increasing and may negatively affect workers mental health. However, the impact of M&A on the risk of developing a mental disorder, rather than psychiatric symptoms, has not been investigated. The objectives of this study were to estimate and compare the 12-month incidence of depressive and anxiety disorders in workers who had and who had not experienced M&A in the last year.

Methods Employees aged 25 and 64 years old were randomly selected from the community and were followed for 1 year (n=3280). Questions about their experience in M&A in the past 12 months were asked. WHO's Composite International Diagnostic Interview–Auto 2.1 was used to assess depressive and anxiety disorders. The 12-month prevalence and 1-year incidence of mental disorders were estimated and compared in relation to M&A.

Results Participants who were exposed to M&A had a significant higher 1-year incidence of generalised anxiety disorder (GAD) (6.7%) than the unexposed (2.4%). They were not different in the incidence of major depressive disorder. The exposed participants were 2.8 times more likely to have had a GAD than others and were about 2.4 times more likely to have developed any anxiety disorders over 1 year.

Conclusions M&A may lead to increased risk of GAD, which may, in return, evolve into major depression. Governments, employers and health professionals should be aware of this and work out plans to reduce the negative health outcomes of M&A.


  • Funding This study was funded by an operating grant from the Canadian Institutes of Health Research (CIHR). However, the CIHR played no role in study design, analysis and interpretation.

  • Competing interests None.

  • Ethics approval Ethics approval was provided by Conjoint Health Research Ethics Board of University of Calgary.

  • Provenance and peer review Not commissioned; externally peer reviewed.

No Related Web Pages

Free sample

This recent issue is free to all users to allow everyone the opportunity to see the full scope and typical content of OEM.
View free sample issue >>

Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.

Navigate This Article