Journal of Psychiatric Research

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1 Journal of Psychiatric Research xxx (2011) 1e9 Contents lists available at SciVerse ScienceDirect Journal of Psychiatric Research journal homepage: Stress and mental disorders in female military personnel: Comparisons between the sexes in a male dominated profession Natalie P. Mota a,b, Maria Medved b, JianLi Wang c, Gordon J.G. Asmundson d, Debbie Whitney e, Jitender Sareen a,b,f, * a Department of Psychiatry, University of Manitoba, Winnipeg, Canada b Department of Psychology, University of Manitoba, Winnipeg, Canada c Departments of Psychiatry and Community Health Sciences, University of Calgary, Calgary, Canada d Department of Psychology, University of Regina, Regina, Canada e Department of Clinical Health Psychology, University of Manitoba, Winnipeg, Canada f Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada article info abstract Article history: Received 24 May 2011 Received in revised form 9 September 2011 Accepted 29 September 2011 Keywords: Female military personnel Traumatic events Occupational stress Mental disorders The proportion of women in militaries is growing; however, many studies in the area of military mental health have been conducted with majority male samples. The present study examined sex differences in trauma exposure, work stress, and mental disorders in the Canadian Community Health Survey e Canadian Forces Supplement, a representative sample of 5155 regular force personnel and 3286 reservists ages 16e54. Past-year DSM-IV mental disorders (depression, generalized anxiety disorder, panic disorder, social phobia, PTSD, and alcohol dependence), lifetime exposure to 28 traumatic events, and work stress were assessed. and reserve female personnel were less likely than males to experience deployment-related traumas, accidents, and several events involving violence (adjusted odds ratio [AOR] range 0.10e0.62). Women were more likely to endorse sexual trauma, partner abuse, and being stalked (AOR range 3.60e13.63). For work stress, regular force women reported higher levels of job demand and stress around social support than men, whereas regular and reserve force women reported less physical exertion. After adjusting for a range of covariates, regular female personnel were more likely than males to have PTSD (AOR 1.88, 99% CI 1.01e3.50), while reservist women were more likely than men to have depression, panic disorder, and any mood or anxiety disorder (AOR range 1.87e6.98). Both regular and reservist women had lower rates of alcohol dependence (AOR range 0.30e0.34). Clinicians working with female personnel should screen for trauma/stressors and mental disorders that are particularly common in this population. Ó 2011 Published by Elsevier Ltd. 1. Introduction 1.1. Sex differences in trauma exposure Women comprise a growing sector of many militaries. Until recently, the research examining stressor/trauma exposure and mental distress in personnel and veteran samples has often been conducted in either exclusively or predominately male samples (Dohrenwend et al., 2006; Fikretoglu et al., 2006). However, examining stressors and mental health profiles in military women, including how they differ from those in men, is becoming increasingly important. * Corresponding author. Department of Psychiatry, University of Manitoba, PZ-430 PsycHealth Centre, 771 Bannatyne Avenue, Winnipeg, Manitoba, Canada, R3E 3N4. Tel.: þ ; fax: þ address: sareen@cc.umanitoba.ca (J. Sareen). Traumatic event exposure can precipitate the development of mental disorders, and a growing number of studies have examined military men and women separately with regard to exposure to trauma/stressors. Women have been found to experience significantly higher rates of sexual harassment and assault (within and outside the military) than men (Belik et al., 2009; Carter-Visscher et al., 2010; Haskell et al., 2010; King et al., 2006; Murdoch et al., 2007; Street et al., 2007, 2009; Vogt et al., 2005). Women have also reported a higher prevalence of a history of several traumatic events, including childhood sexual abuse and intimate partner violence (e.g., Belik et al., 2009; Carter-Visscher et al., 2010; Rosen and Martin, 1996; Street et al., 2009). With regard to militaryspecific stressors, women have endorsed more general /$ e see front matter Ó 2011 Published by Elsevier Ltd. doi: /j.jpsychires

2 2 N.P. Mota et al. / Journal of Psychiatric Research xxx (2011) 1e9 harassment (King et al., 2006), and lower levels of pre-deployment preparedness and deployment-related social support (King et al., 2006; Vogt et al., 2005; Vogt et al., 2008a). Military men typically report more combat exposure, violencerelated events (e.g., being badly beaten), natural and manmade disasters, and accidents (Belik et al., 2009; Hourani et al., 2003; King et al., 2006; Vogt et al., 2005; Vogt et al., 2008a). No sex differences have been found for several stressors/traumatic events, including worries related to life/family disruption, physical abuse by a parent/caregiver, and a sudden death of someone close (Belik et al., 2009; Carter-Visscher et al., 2010; King et al., 2006; Vogt et al., 2005; Vogt et al., 2008a) Sex differences across mental disorders Exposure to traumatic events and military-related stressors have been found to be associated with negative mental health outcomes (Belik et al., 2009; Carter-Visscher et al., 2010; King et al., 2006; King et al., 2008; Murdoch et al., 2007; Sareen et al., 2007, 2008; Vogt et al., 2005; ;Vogt et al., 2008b). With regard to sex differences across mental disorders, several studies in personnel and veteran samples have shown women to have a higher prevalence of symptomatology, including depression, PTSD, and suicidal ideation (Haskell et al., 2010; Rona et al., 2007; Sareen et al., 2008; Vogt et al., 2005). Military men typically endorse more alcohol use and related disorders than women (Ames et al., 2007; Bray et al., 1999; Rona et al., 2007; Sareen et al., 2008). However, some studies have failed to find such differences or have shown higher rates of some psychological disorders in males (Bray et al., 1999; Haskell et al., 2010; Jones et al., 2006; Rona et al., 2007; Street et al., 2009) Sex differences in work stress Research in civilian samples has shown that higher perceived levels of work stress can be detrimental to employees mental health (Virtanen et al., 2007; Wang, 2004, 2005; Wang et al., 2008). Work stress in the military can be substantial and has demonstrated associations with negative outcomes (Bray et al., 1999, 2001, 2010; Hourani et al., 2006; Pflanz and Ogle, 2006). Only a handful of studies using military samples have examined sex differences in occupational stress. Women have shown more strain (Bridger et al., 2008; Hourani et al., 2006), although similar proportions of men and women experienced high stress levels in another sample (Bray et al., 1999, 2001). However, a relatively high proportion of female personnel reported experiencing stress around being a woman in the military (Bray et al., 2001), and another study found that a greater proportion of women than men reported past-year work problems (Ames et al., 2007) Sex differences across sociodemographic variables Military males and females have been found to differ on a number of sociodemographic variables. Some studies have found that women are less likely to be married and more likely to be non- Caucasian, of younger age, and of lower military rank (Haskell et al., 2010; Murdoch et al., 2007; Rosen and Martin, 1996). Such factors might be important confounding variables to consider when investigating sex differences across stress and mental disorders versus reserve force personnel In several studies, regular and reserve/national Guard personnel have differed with respect to trauma/stressor exposure and mental disorder symptomatology (Browne et al., 2007; King et al., 2006; Milliken et al., 2007; Vogt et al., 2008b). Such traumatic events have included combat exposure, other aspects of war (e.g., handling/seeing dying or dead bodies), and deployment social support/unit cohesion (Browne et al., 2007; King et al., 2006; Milliken et al., 2007; Vogt et al., 2008b). However, findings have been mixed for several of these variables and inconsistent with regard to differences in psychopathology (Browne et al., 2007; Iowa Persian Gulf Study Group, 1997; Hotopf et al., 2006; Iversen et al., 2009; King et al., 2006; Kinley et al., 2011; Mather et al., 2010; Milliken et al., 2007; Pietrzak et al., 2010; Vogt et al., 2008b). Further, a recent study in a small sample of veterans examined threeeway interactions (sex by stressor by regular versus reserve status) in relation to symptoms of PTSD (Vogt et al., 2008b). The authors found that the associations between a number of stressors and increased symptomatology were particularly strong in active duty women and National Guard/reserve status men (Vogt et al., 2008b). Such findings highlight the importance of examining sex differences within regular and reserve personnel separately Rationale and current study Previous research examining sex differences with regard to the above constructs in the military has been limited by several factors. First, most studies have investigated mental disorders using selfreport questionnaires instead of standardized diagnostic interviews. Second, the few studies that have examined work stress have used one or two self-reported yes/no questions rather than a multi-faceted assessment. Third, many previous studies have not adjusted for potential confounding factors. Fourth, most previous studies have not distinguished between regular and reserve status personnel. In the present study, we have addressed the limitations of past research by using a standardized assessment of mental disorders and a validated measure of work stress to examine sex differences 1) in the exposure to 28 lifetime traumatic events, 2) across several dimensions of past-year work stress, and 3) in the prevalence of several past-year DSM-IV mental disorders in a representative sample of forces personnel. We also accounted for several potentially confounding factors in our analyses and stratified by regular versus reserve status. To our knowledge, no previous study has been able to address all of these issues under one investigation. Our primary hypotheses were the following: 1a: Female personnel would endorse less combat exposure and accident-type traumas than male personnel. 1b: Female personnel would endorse more sexual trauma and intimate partner violence than male personnel. 2: Female personnel would show more stress than male personnel on several dimensions of work stress examined. 3a: Female personnel would report a higher prevalence of depression and anxiety disorders than male personnel. 3b: Female personnel would report less alcohol dependence than men. 2. Method 2.1. Participants Data from the Canadian Community Health Survey on Mental Health and Wellbeing: Canadian Forces Supplement (CCHS-CFS) were used. The CCHS-CFS was a representative survey of active military personnel in the Canadian Forces conducted by Statistics

3 N.P. Mota et al. / Journal of Psychiatric Research xxx (2011) 1e9 3 Canada and the Department of National Defence. The survey, conducted in 2002, included 5155 regular and 3286 reserve force personnel aged 16e54, which consisted of 5849 men and 2592 women. Other sociodemographic characteristics of respondents can be found in Table Procedure Details on the design and methodology of the CCHS-CFS can be found elsewhere (Statistics Canada, 2003). A multistage sampling strategy was employed to obtain representation of the Canadian military population, with stratifications being made by regular versus reserve personnel, rank, and sex. The response rates were 79.5% and 83.5% for regular and reserve force members, respectively. Interviews were mostly conducted face-to-face in on-base rooms and were administered by trained lay interviewers from Statistics Canada using computer-assisted interviewing. The CCHS-CFS is safely held at the Research Data Centre at the University of Manitoba in Winnipeg, Canada, and all analyses were conducted there. Due to the anonymized and secondary nature of the data, approval from an institutional ethics board was not needed Measures Traumatic events The lifetime exposure of 28 traumatic events was assessed in the CCHS-CFS and asked in the form of yes/no questions to all respondents. Events were grouped conceptually into five categories in line with a previous study with this sample (Belik et al., 2009): sexual trauma, other interpersonal, accident and/or unexpected, deployment-related, and civilian in war or refugee Work stress Work stress in the past-year was assessed using a 12-item, abbreviated version of the Job Content Questionnaire (JCQ) (Karasek et al., 1998), which has been previously used (Wang, 2004; Wang et al., 2008). Six dimensions of work stress were queried, including skill discretion/demand (3 items, range ¼ 0e12), decision authority/control (2 items, range ¼ 0e8), psychological demand (2 items, range ¼ 0e8), job insecurity (1 item, range ¼ 0e4), physical exertion (1 item, range ¼ 0e4), and social support from colleagues and supervisors (3 items, range ¼ 0e12). Each question was measured on a 5-point Likert scale (0e4) from strongly agree to strongly disagree. The Cronbach s alpha coefficient for the JCQ scale was a ¼ 0.52 (0.33 for skill discretion, 0.66 for decision authority, 0.42 for psychological demand, and 0.48 for social support). As noted in a previous paper that used the JCQ (Wang et al., 2008), internal consistency reliability is not always high when a scale includes different dimensions (Boyle, 1985). A few items were reversed coded by Statistics Canada so that for all items, higher scores delineated higher stress. Responses for each dimension were examined as continuous variables because their skewness indexes were less than 1. The exception was job insecurity where the majority of participants replied strongly agree to their job security being good. Thus, the item was dichotomized as strongly agree versus the other response choices Mental disorders The World Health Organization Composite International Diagnostic Interview (WHO-CIDI) version 2.1 was used to assess mental disorders. The WHO-CIDI is a standardized diagnostic interview with well-documented reliability and validity (Haro et al., 2006; Kessler et al., 2004; Kessler and Ustun, 2004). The following past- Table 1 Prevalence of sociodemographic and military factors in women and men and sex differences across these variables. Males Females OR (99% CI) Males Females OR (99% CI) Sociodemographic Variables % % % % Age 16e e (0.71e1.33) (0.99e1.68) 35e (0.61e1.10) (1.08e1.76)*** 45e (0.41e0.80)*** (0.40e0.78)*** Marital Status Married/Common-law Separated/widowed/Divorced (1.53e2.66)*** (0.93e2.21) Never married (1.50e2.22)*** (0.63e0.93)*** Household Income >80, ,000e79, (0.35e0.50)*** (0.75e1.24) 30,000e49, (0.61e0.98)** (1.10e1.94)*** <29, (0.59e1.46) (0.91e1.84) Education Bachelor s degree or higher Postsecondary school below bachelor s (0.69e0.92)*** (0.65e1.05) High school or less (0.47e0.63)*** (0.43e0.75)*** Type of Occupation Land Air (1.61e2.32)*** (1.37e2.54)*** Sea/Communications (0.98e1.53) (1.42e2.30)*** Rank Junior Senior (0.50e0.74)*** (0.53e0.88)*** Officer (1.04e1.22)*** (0.55e0.64)*** Note. Percentages are weighted. OR e Odds Ratio. **p < 0.01; ***p < Bold values represents statistically significant.

4 4 N.P. Mota et al. / Journal of Psychiatric Research xxx (2011) 1e9 year disorders were examined in the present study: major depression, panic disorder, social phobia, generalized anxiety, PTSD, and any mood or anxiety disorder. Alcohol dependence was assessed using the CIDI Short Form, where endorsement of three or more symptoms was considered alcohol dependence (Kessler et al., 1998) Sociodemographic and military variables The following sociodemographic variables were examined in the present study: Age (16e24, 25e34, 35e44, 45e64 years), household income ($29,999 or less, $30,000-$49,999, $50,000- $79,999, $80,000 and greater), marital status (married/commonlaw, divorced/separated, widowed), and education (postsecondary degree, some postsecondary education, high school or less). Military rank (Junior, Senior, Officer) and type of service (land, air, and sea/communications) were also included. Due to a low prevalence for the communications category, it was collapsed with sea, the next smallest category in the variable Statistical analyses Correct statistical weights were supplied by Statistics Canada and applied to all analyses to make possible the representativeness of Canadian Forces personnel. The bootstrapping method of error estimation was also applied using SUDAAN software (Research Triangle Institute, 2004) because it adjusts for the complex sample design of the survey. Differences between regular and reserve status female personnel were calculated across outcome variables to verify that applying a regular versus reserve stratification for remaining analyses was warranted. All subsequent analyses were stratified in regular versus reserve personnel. First, the prevalence of sociodemographic and military variables was calculated in men and women. Unadjusted logistic regression analyses tested for sex differences across these factors. Second, multiple regression analyses adjusted for the variables above calculated sex differences in the exposure to the 28 lifetime traumatic events. Third, sex differences across each work stress variable were examined using multiple linear regression analysis (multiple logistic regression was used for the dichotomized variable), adjusting for sociodemographic and military variables. Lastly, multiple logistic regression analyses were used to investigate sex differences across mental disorders. Two models were tested. The first adjusted for sociodemographic and military covariates. The second model adjusted for 1) sociodemographic and military variables, 2) a count variable of the number of traumatic events experienced for each category of traumatic event (sexual trauma, other interpersonal, accident and/ or unexpected, deployment-related, civilian in war or refugee), and 3) each work stress variable. 3. Results Analyses examining differences across trauma exposure, work stress, and mental disorders in regular and reserve female personnel showed several differences. women were less likely than regular force women to have been exposed to deployment-related events (AOR range 0.25e0.45), to have witnessed someone being badly injured, killed, or to have seen a dead body (AOR 0.67, 99% CI 0.50e0.91), and to have been badly beaten by parents/guardians (AOR 0.45, 99% CI 0.26e0.78). force women reported higher levels of work stress related to job control, psychological demand, and physical exertion. However, reserve force women were more likely to report job insecurity (AOR 5.47, 99% CI 4.25e7.04). Finally, in the model adjusting for sociodemographic and military variables, trauma exposure, and work stress, reserve women were more likely than regular force women to have panic disorder (AOR 2.41, 99 CI% 1.03e5.62). No other differences were found (results in female and male personnel available upon request). Table 1 shows sex differences across sociodemographic and military variables. In regular status personnel, women were less likely than men to be in the 45e64 year old age group, in the $30,000-$79,999 household income range, to have an education level below a Bachelor s degree, and to be of senior rank. status female personnel were more likely to be separated/widowed/divorced and never married, to work in air operations, and to be of officer rank. In reserve status personnel, women were less likely to be in the 45e64 age range, to have never been married, to have an education of high school or less, and to be of officer or senior status. female personnel were more likely than their male counterparts to be between 35 and 44 years, to be in the $30,000-$49,999 household income category, and to work in air, sea, or communications. Table 2 shows sex differences in exposure to each lifetime traumatic event. Hypothesis 1a, that female personnel would endorse less combat exposure and accidents than male personnel, was supported. Women in both regular and reservist roles were less likely than males to report lifetime exposure to deployment-related traumas (adjusted odds ratio [AOR] range 0.10e0.43) and less likely to experience several events in the accidents/other unexpected events category (AOR range 0.23e0.62). Other events for which women showed a lower likelihood of exposure included being civilians in war, badly beaten by anyone else, mugged, held up or threatened with a weapon, and endorsing other traumatic events (AOR range 0.20e0.62). force female personnel were additionally less likely than regular force males to have been kidnapped or held captive (AOR 0.45, 99% CI 0.23e0.87) and more likely to have witnessed physical violence as a child at home (AOR 1.29, 99% CI 1.00e1.65). Hypothesis 1b, that female personnel would endorse more sexual trauma and intimate partner violence than males, was also supported. Both regular and reserve women were more likely than men to have experienced spousal/partner abuse, being stalked, and sexual trauma (AOR range 3.60e13.63). Table 3 displays sex differences across the dimensions of pastyear work stress, adjusted for covariates. Hypothesis 2, that female personnel would show higher levels than males on several dimensions of work stress, was only partially supported. force women reported higher levels than regular force males with regard to stress related to job demand and social support from co-workers and supervisors. However, both regular and reserve force women reported significantly lower levels than men of stress related to physical exertion, and no other significant differences were found. Sex differences in past-year mental disorders are displayed in Table 4. Hypothesis 3a, that female personnel would show a higher prevalence of depression and anxiety disorders, was partially supported in regular force personnel, and mostly supported in reserve force personnel. In the fully adjusted statistical model, reserve force women were more likely than men to have PTSD (AOR 1.88, 99% CI 1.01e3.50). Meanwhile, in reserve force personnel, women were more likely than males to have depression, panic disorder, and any mood or anxiety disorder in the same model (AOR range 1.87e6.98). Finally, Hypothesis 3b, that there would be lower rates of alcohol dependence in military women than in men, was supported. Women were less likely to have alcohol dependence both in regular (AOR 0.30, 99% CI 0.15e0.63) and reserve force personnel (AOR 0.34, 99% CI 0.16e0.72). 4. Discussion The present study had several important findings with regard to sex differences across work stress, trauma, and mental disorders in military personnel. First, both regular and reserve force women were

5 N.P. Mota et al. / Journal of Psychiatric Research xxx (2011) 1e9 5 Table 2 Sex Differences in Exposure to Traumatic Events. Males Females Males Females Lifetime Traumatic Events Deployment-Related Combat Exposure % AOR (99% CI) (0.28e0.54)*** (0.25e0.75)*** Peacekeeper or Relief Worker % AOR (99% CI) (0.30e0.46)*** (0.19e0.47)*** Purposely Caused Injury, Tortured, or Killed Another % AOR (99% CI) (0.03e0.33)*** (0.05e0.50)*** Witnessing Atrocities % AOR (99% CI) (0.17e0.35)*** (0.16e0.58)*** Accident or Other Unexpected Life-Threatening Motor Vehicle Accident % AOR (99% CI) (0.38e0.58)*** (0.37e0.66)*** Other Life-Threatening Accident % AOR (99% CI) (0.21e0.41)*** (0.22e0.54)*** Toxic Chemical or Substance Exposure % AOR (99% CI) (0.29e0.48)*** (0.21e0.44)*** Natural Disaster % AOR (99% CI) (0.49e0.78)*** (0.51e1.02) Manmade Disaster % AOR (99% CI) (0.27e0.57)*** (0.25e0.64)*** Someone Close Dying Unexpectedly % AOR (99% CI) (0.81e1.16) (0.78e1.27) Son or Daughter with Life-Threatening Illness/Injury % AOR (99% CI) (0.43e1.47) Life-Threatening Illness % AOR (99% CI) (0.59e1.16) (0.58e1.46) Witnessed Someone Being Badly Injured, Killed, or Dead Body % AOR (99% CI) (0.31e0.45)*** (0.29e0.50)*** Accidentally Caused Injury or Death of Someone Else % AOR (99% CI) (0.13e0.52)*** (0.06e0.84)** Sexual Trauma Sexual Assault % AOR (99% CI) (7.34e14.70)*** (8.22e22.60)*** Sexual Harassment % AOR (99% CI) (6.48e10.46)*** (6.61e13.07)*** Other Interpersonal Badly Beaten by Parents/Guardians % AOR (99% CI) (0.82e1.62) (0.42e1.25) Badly Beaten by Spouse or Romantic Partner % AOR (99% CI) (3.96e10.99)*** (3.47e24.42)*** Badly Beaten by Anyone Else % AOR (99% CI) (0.14e0.33)*** (0.12e0.36)*** Mugged, Held Up, Threatened With Weapon % AOR (99% CI) (0.22e0.40)*** (0.24e0.49)*** Stalked % (continued on next page)

6 6 N.P. Mota et al. / Journal of Psychiatric Research xxx (2011) 1e9 Table 2 (continued ) Males Females Males Females AOR (99% CI) (3.47e6.84)*** (2.37e5.47)*** Witnessing Physical Violence As Child at Home % AOR (99% CI) (1.00e1.65)** (0.99e2.02) Kidnapped or Held Captive % AOR (99% CI) (0.23e0.87)** (0.41e3.06) Civilian in War or Refugee Unarmed Civilian % AOR (99% CI) (0.38e1.00)** (0.26e0.90)** Civilian in Ongoing Terror % AOR (99% CI) (0.33e0.94)** (0.29e0.84)*** Refugee n (%) AOR (99% CI) Traumatic Experience of Someone Close % AOR (99% CI) (0.79e1.27) (0.75e1.41) Other % AOR (99% CI) (0.26e0.57)*** (0.24e0.72)*** Note. AOR- Adjusted for age, marital status, household income, education, type of service, and rank. **p < 0.01; ***p < Not shown due to data warnings that the statistical model was approaching infinity. Bold values represents statistically significant. more likely than their male counterparts to endorse exposure to sexual trauma. This finding is consistent with previous research showing that female personnel experience more military-related and pre-military/lifetime sexual harassment and abuse (Belik et al., 2009; Carter-Visscher et al., 2010; Haskell et al., 2010; King et al., 2006; Murdoch et al., 2007; Rosen and Martin, 1996; Street et al., 2007, 2009; Vogt et al., 2005). In the current study, women in both types of forces were also much more likely to report intimate partner violence and being stalked. Further, regular force women were more likely than regular force men to have witnessed domestic violence as a child, and this difference approached significance in reserve personnel. No sex difference was found with regard to observing physical fights between parents in the study by Carter- Visscher et al. (2010), and the current study identified similar rates in males and females in being badly beaten by parents/guardians. Nonetheless, it is possible that military women come from more Table 3 Sex Differences in Work Stress. Males Females Males Females Work Stress Mean (SE) Mean (SE) Mean (SE) Mean (SE) Subscales Demand 3.77 (0.03) 4.03 (0.05)*** 4.17 (0.05) 4.19 (0.07) Control 2.99 (0.03) 3.11 (0.05) 3.06 (0.04) 3.19 (0.06) Psychological 5.07 (0.03) 5.14 (0.05) 4.61 (0.04) 4.70 (0.06) Demand Physical Exertion 2.20 (0.02) 1.95 (0.03)*** 2.31 (0.03) 1.87 (0.04)*** Social Support 3.85 (0.04) 4.08 (0.06)*** 3.64 (0.05) 3.87 (0.07) AOR (99% CI) AOR (99% CI) AOR (99% CI) AOR (99% CI) Insecurity (0.78e1.18) (0.73e1.14) Note. Mean and AOR e Adjusted for age, marital status, household income, education, type of service, and rank. **p < 0.01; ***p < Bold values represents statistically significant. Table 4 Associations Between Sex and Mental Disorders. Males Females Males Females Past Year Mental Disorders Major Depression % AOR-1 (99% CI) (1.05e1.97)** (1.45e4.13)*** AOR-2 (99% CI) (0.82e1.94) (1.01e3.46)** Panic Disorder % AOR-1 (99% CI) (1.56e13.37)*** AOR-2 (99% CI) (2.20e22.13)*** Social Phobia % AOR-1 (99% CI) (1.02e2.35)** (0.85e3.77) AOR-2 (99% CI) (0.88e2.71) (0.71e4.57) Generalized Anxiety Disorder % AOR-1 (99% CI) (0.75e2.50) (0.36e3.11) AOR-2 (99% CI) (0.49e2.49) (0.20e2.50) Posttraumatic Stress Disorder % AOR-1 (99% CI) (0.88e2.25) (0.83e6.44) AOR-2 (99% CI) (1.01e3.50)** (0.87e12.82) Any Mood or Anxiety Disorder % AOR-1 (99% CI) (1.17e1.93)*** (1.74e3.87)*** AOR-2 (99% CI) (0.94e1.88) (1.35e3.50)*** Alcohol Dependence % AOR-1 (99% CI) (0.18e0.60)*** (0.23e0.81)*** AOR-2 (99% CI) (0.15e0.63)*** (0.16e0.72)*** Note. AOR-1- Adjusted for age, marital status, household income, education, type of service, and rank. AOR-2 e Adjusted for age, marital status, household income, education, type of service, rank, each category of traumatic events, and each work stress variable. **p < 0.01; ***p < Not shown due to data warnings that the statistical model was approaching infinity. Bold values represents statistically significant.

7 N.P. Mota et al. / Journal of Psychiatric Research xxx (2011) 1e9 7 disruptive childhood environments than men (King et al., 2006). Investigating sex differences in childhood adversity in military populations remains an important future direction. Both regular and reserve force women were less likely than men to report war-related events, a number of accidents and other unexpected events (e.g., chemical or substance exposure, motor vehicle accidents), and events relating to non-domestic physical violence. These findings are mostly consistent with past research (Hourani et al., 2003; King et al., 2006; Vogt et al., 2005; Vogt et al., 2008a). For several of these events, for example, witnessing atrocities and seeing a dead body, the sex differences found are likely reflective of the larger numbers of men who get deployed in combat-related operations (Canadian Forces National Report to the Committee for Women in NATO Forces, 2009). Further, men in general tend to be involved in more physical aggressiveness and risk-taking behavior (Byrnes et al., 1999; Harris and Knight- Bohnhoff, 1996; Zeichner et al., 2003). force women also reported higher levels than men on two of the six aspects of work stress, including job demand and social support from colleagues and supervisors. The relationship between sex and social support in reserve personnel approached statistical significance. Civilian women also report more job demand than men (Wang et al., 2008), and the current finding may not be unique to the military environment. Regarding the sex difference in social support at work, this finding has been supported by other military studies (King et al., 2006; Vogt et al., 2005). It is recommended that the military continue exerting effort on achieving the full integration of female personnel, particularly for those women who have made a career out of their military service. Finally, both regular and reserve force men reported more physical exertion than women. This finding is likely reflective of more men than women participating in more physically taxing military roles (e.g., combat). In the present study, several sex differences were found with regard to mental disorders. Both regular and reserve female personnel were more likely than male personnel to have past-year major depression and any mood and anxiety disorder. Additionally, regular force women were more likely to have social phobia, while reserve force women were more likely than men to have panic disorder. Both regular and reserve force men showed higher rates of alcohol dependence. Such findings are generally in line with several studies in military samples showing higher rates of some psychopathology in women (Ames et al., 2007; Ferrier-Auerbach et al., 2010; Jones et al., 2006; Sareen et al., 2008; Vogt et al., 2005). In the more adjusted model, the sex differences in major depression, social phobia, and any mood and anxiety disorder in regular force personnel failed to reach significance, suggesting that exposure to traumatic events and work stress were accounting for women s higher likelihood of having these disorders. Conversely, the relationship between sex and PTSD became stronger and reached significance in the more stringent model in regular force personnel, with women showing higher rates than males. Finally, all previous sex differences in reserve personnel remained, even after adjustments. It is not surprising that numerous sex differences in mental disorder prevalence failed to reach significance after adjusting for work stress and trauma. Kanter s theory explains why the military environment, with its sex ratio of 85:15, may be especially stressful for women (Kanter, 1997, in Hunt and Emslie, 1998). Due to being the minority sex, this theory posits that women are treated as the others and given stereotyped traits, which could contribute to greater work stress and also influence well-being. However, in the present study, female reservists were more likely than males to have several disorders, even after adjusting for traumatic events and work stress. Civilian women have also been found to have more internalizing psychopathology than males (Piccinelli and Wilkinson, 2000; Seedat et al., 2009), and the differences between military men and women with respect to these mental disorders may not be unique to this environment. Moreover, women have been found to experience a higher level of certain premilitary stressors, including childhood sexual abuse and adult sexual assault (Carter-Visscher et al., 2010; Rosen and Martin, 1996). It is possible that women enter military service with an increased vulnerability for developing mental illness. Future work needs to examine mental disorders in women in non-traditional gendered workplaces like the military in relation to other, more genderbalanced occupations. In addition, future research needs longitudinal designs with baseline as well as post trauma/military service assessments of mental illness (Fear et al., 2010). This work is needed in order to examine the temporal role of trauma and work stress on sex differences across mental disorders. The current findings offer a number of important clinical implications. Mental health professionals working with female personnel should assess and monitor those traumatic events, types of work stress, and mental disorders to which this population is most vulnerable. Clinicians should also recognize that the likelihood of experiencing certain events varies with both sex and regular versus reserve personnel status. Finally, treating trauma histories in regular force female personnel and working with them to manage challenges in the workplace may decrease sex differences in the prevalence of some mental disorders. The findings of this study should be interpreted in the context of the following limitations. First, the CCHS-CFS is a cross-sectional survey and the temporal relationship of stressor exposure and the development of mental disorders in relation to military service cannot be discerned. This is particularly true of the traumatic events in the study, for which lifetime exposure was assessed. Second, trained lay interviewers rather than clinicians assessed mental disorders in the CCHS-CFS, although overall good concordance has been shown with clinician-based diagnoses (Kessler et al., 2004). Third, drug abuse and dependence were not assessed in the CCHS-CFS. Finally, the survey was collected in 2002, and future studies are required in Canadian Forces samples involved in Afghanistan. The present study examined sex differences in trauma exposure, mental disorders, and work stress in a representative sample of regular and reserve Canadian Forces personnel. Several sex differences were found across constructs. Results can assist mental health professionals working with military men and women by identifying specific areas that may need screening within each sex. Role of funding source The present study was funded by a Canadian Institutes of Health Research (CIHR) New Investigator Award (#152348) (Sareen), a CIHR operating grant (Sareen), and a Social Sciences and Humanities Research Council (SSHRC) Graduate Scholarship- Doctoral Award (Mota). These funding agencies had no role in any part of the present study or in manuscript preparation and approval. Conflict of interest No author has any conflicts of interest to disclose. Contributors Natalie Mota assisted in the study design, conducted the statistical analyses, analyzed and interpreted the data, and wrote the manuscript. Maria Medved, JianLi Wang, Gordon Asmundson, and Debbie Whitney assisted in interpreting the data and reading several drafts of the manuscript for intellectual content. Jitender Sareen assisted in study design and conceptualization,

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