The project Danish soldiers after a war-zone deployment has investigated some consequences of being deployed. In September 2012 we published the final report. The report focuses on mental health among the 26,000 soldiers.
We investigate mental health through administrative registers by taking advantage of the fact that in Denmark, from birth or from immigration date, every person is attributed a unique personal code called a CPR number (Central Personal Register). This code is used every time a person is in contact with a public body. The existence of this personal number makes it possible to follow an individual’s use of health care (e.g., contacts to psychiatrist, type of diagnoses and purchase of medication for mental diseases). All this information is stored by Statistics Denmark and can be linked with other data thanks to the CPR number. All individuals are followed until they either die or emigrate.
The data basis comprises register data from Defence Denmark, Statistics Denmark, the Danish Health and Medicines Authority and the National Board of Industrial Injuries in Denmark.
The report compares the mental health of the soldiers before and after their deployment in the period 1995-2010. We can compare the younger soldiers (born 1975-1982) with a control group. As our control group we used men born 1975-1982 who were declared eligible at the mandatory Armed Forces Day (AFD) meeting but were not deployed. On average 50% of a birth cohort is declared eligible. For the other soldiers we describe their mental health before and after deployment.
We examine psychological injuries categorized as psychiatric diagnoses, purchases of medication for mental diseases, contacts with the psychiatric health system, and treatment for substance abuse.
Some of the main conclusions of the report are:
- After deployment almost 17% of the 26,000 soldiers deployed in the period 1992-2009 are registered either with a psychiatric diagnosis, purchase of medication for mental diseases, or treatment for substance abuse. None of them were registered for these psychological injuries before deployment.
- Soldiers previously deployed to the former Yugoslavia in the early 1990s are particularly likely to be registered with psychological injuries, but soldiers repatriated from missions in Afghanistan and Iraq in the period 2005-2009 have also been registered with injuries after deployment.
- When comparing soldiers born from 1975-1982 with the control group, we find that in general those deployed have fewer psychiatric diagnoses and less contact with the psychiatric healthcare system. Furthermore, fewer buy medication for mental diseases and fewer have been in treatment for substance abuse. Moreover, we find lower mortality rates for the deployed soldiers than for the control group.
- Before deployment, the incidence of mental disease is lower for soldiers than for the people in the control group, but around three years after deployment there is a relatively sharp increase in mental disease incidence for the deployed soldiers compared with the control group. This increase means that after a few years, the incidence of mental disease is similar in the two groups.
- Furthermore, the deployed soldiers report more occupational mental diseases than the control group, and in general they report more industrial injuries.
- Finally we conduct a drop-out analysis on the basis of follow-up studies from the Department of Military Psychology (MPA). The MPA send these questionnaires in order to identify soldiers that may need psychological help after their mission. The objective of the drop-out analysis is to figure out whether the people who have not responded are distinct from those who have responded. In this way it is possible to see who Danish Defence contact in connection with their follow-up studies. We link the list of respondents and non-respondents to register data from the Danish Health and Medicines Authority and find that soldiers deployed in the period 2007-2009, who have not responded to the questionnaire, have poorer mental health than those who responded to the questionnaire in terms of more psychiatric diagnoses and higher purchase of medication for mental diseases.