The effects of deployment to military combat on the individual and the family system are wide-reaching and can be severe. According to the U.S. Department of Defense, there were nearly 3.5 million current military personnel in 2021 and 19.3 million veterans in 2020 [1,2]. The Army has the largest number of active duty members, followed by the Navy, the Air Force, and the Marine Corps [1]. Military service presents its own set of risk and protective factors for a variety of mental health issues, including post-traumatic stress disorder (PTSD), traumatic brain injury (TBI), depression and suicide, substance abuse, and interpersonal violence. In particular, transitioning from combat back to home life can be particularly trying for veterans and their families.

Military personnel may confront numerous potentially traumatizing experiences, including military-specific events and those experienced by civilians. Research suggests the most common traumatic events experienced during active duty are witnessing someone badly injured or killed or unexpectedly seeing a dead body. Events most likely to result in the development of PTSD include witnessing atrocities, accidentally injuring or killing another person, and other interpersonal traumas, such as rape, domestic violence, and being stalked, kidnapped, or held captive [6,12].

With innocent civilians used as human shields, children used as "bait" for attacks, calm moments erupting into death and devastation in seconds, and violations of the rules of engagement, the nature of the Iraq and Afghanistan wars impose on the returning veteran an unnatural recalibration of security and sanity. Among returning war veterans, the most common problems involve somatic, emotional, cognitive, behavioral, interpersonal, and psychosocial components. Somatic concerns appear as primary and middle (sleep-maintenance) insomnia, fatigue, headaches, tinnitus, impotence, restlessness, and chronic pain. Emotional and psychological complaints may involve nightmares, racing thoughts (particularly at bedtime), generalized and social anxiety, anger and irritability, impulsive hostility, emotional numbing, hypervigilance, complicated grief, and despair [7].

Since 2007, the suicide rates in the Army and Marine Corps have surpassed general population rates; these statistics remain unchanged as of data presented in 2019 [19]. Factors with the greatest association to suicide risk include depression, relationship strain, financial and vocational loss, and magnitude of life impairment. Clinical presentations with the highest prediction of potential future suicidal behavior are the presence of overwhelming negative thoughts and hopelessness over the future [20].

Veterans often possess many risk factors for attempting or completing suicide. These include combat exposure (particularly deployment to a combat theater and/or adverse deployment experiences), combat wounds, PTSD and other mental health problems, comorbid major depression, TBI, poor social support, feelings of not belonging or of being a burden to others or society, acquired ability to inflict lethal self-injury, and access to lethal means [28,36,37]. There is conflicting evidence of the role of PTSD in suicide risk, with some studies finding PTSD diagnosis to be protective while others indicating it increases risk. Other possible risk factors include [26]:

The VA defines military sexual trauma as "sexual assault or repeated, threatening sexual harassment that occurred while the veteran was in the military" [48]. This can include rape (nonconsenting, forced, or coerced sexual activity); unwanted sexual touching or grabbing; threatening, offensive remarks about a person's body or sexual activities; and/or threatening or unwelcome sexual advances [30,48]. In 2021, the Department of Defense estimated that 35,875 service members, including 19,255 women and 16,620 men, experienced unwanted contact or penetrative sexual assault; however, only 20% of these individuals made a report of the incident [49]. In a survey of 60,000 veterans who served during the Operations Enduring Freedom and Iraqi Freedom eras, approximately 41% of women and 4% of men reported experiencing military sexual trauma [50]. Female Marines and Navy veterans were at an increased risk compared with female Air Force veterans, and both men and women who experienced combat exposure during deployment had increased risk for sexual trauma compared with those who did not [50]. In general, deployment was a protective factor for male veterans, but not for female veterans. In a separate study of 13,262 female military members, significant risk factors for sexual stressors included younger age, recent separation or divorce, service in the Marine Corps, positive screen for a baseline mental health condition, moderate/severe life stress, and prior sexual stressor experiences [51].

Although military sexual assault is relatively common, victims remain reluctant to report their experiences [52]. It is recommended that all health and mental health professionals ask their veteran patients about experiences of sexual assault, even if they served many years previously. The following questions may be included in history-taking [4]:

Clinical care providers should be alert for, and responsive to, the emotional trauma sustained by the sexual assault victim. In the hours following an assault, these patients exhibit a range of emotional responses, including fear, panic, shame, anger, mistrust, and denial. They are in need of emotional support, comfort, and the assurance of protection. Often, there is a need for reassurance that the victim is not at fault, no matter the circumstances surrounding the assault. Rape crisis counseling and social services should be enlisted early to assist in the care of the patient and to develop a discharge plan that addresses emotional needs, support systems, safety issues, and follow-up care.

The military also provides services for victims of sexual trauma. The VA provides free services to help veterans overcome sexual trauma, even for veterans who do not qualify for other VA care or who have not reported the incident(s) [53]. The Department of Defense offers anonymous crisis and support help for victims via its Safe Helpline https://www.safehelpline.org or (877) 995-5247. Resources available include one-on-one live chat, anonymous support group discussions, and resources for reporting retaliation [53].

Deployment and moving are potential risk factors for domestic violence. In a 2013 study, 2% of married deployed personnel had perpetrated physical or emotional spousal abuse during the study period [65]. Rates of moderate and severe abuse and abuse involving alcohol were significantly higher in the post-deployment period.

Some studies show that female veterans are at increased risk of physical and sexual violence from their intimate partners (33%) compared with nonveteran counterparts (23.8%) [66]. Research indicates that female veterans who experienced previous childhood sexual abuse are three times more likely to be victims of spousal abuse, and those who experienced an unwanted incidence of sexual victimization during military service were more likely to have experienced interpersonal violence in the last year [67]. Being in the Army (versus other military branches) is also a risk factor for past-year victimization [67].

In another study, a total of 716 married military service men stationed in a U.S. Army post in Alaska participated in a survey. Almost one-third of the men (31.6%) reported engaging in some act of aggression against their partner in the last 12 months. Nine percent disclosed having engaged in at least one moderate-to-severe act of aggression [69].

Race is another factor. When researchers examined White and African American spouse abuse cases documented in the Army Central Registry, rates were higher among all age brackets for African Americans. It is not clear what specific factors are influencing these different rates, but a systematic bias may exist in the referral process [60]. It is also possible that referrals are made to the Family Advocacy Program due to stereotypical perceptions that African American families are more violent. The authors recommended further longitudinal studies to examine cultural-specific factors that contribute to these rates.

It has also been speculated that exposure to the trauma of combat and the development of post-traumatic stress symptoms provokes military veterans to be violent at home [56]. Furthermore, when these veterans do obtain treatment, either voluntarily or as mandated, many do not complete their treatment regimens [56].

Intermittent explosive disorder is included under the general category of disruptive, impulse-control, and conduct disorders in the text revision of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) [71]. Approximately 2.7% of the general public meets the diagnostic criteria for this disorder, but it is much more common among military veterans. In one study of nondeployed U.S. Army personnel, 11.2% of participants met the criteria for intermittent explosive disorder in the past 30 days; it was the most prevalent mental disorder, surpassing PTSD and attention deficit hyperactivity disorder [72].

As noted, times of transition are particularly stressful for veterans and military families, and special care should be taken during these periods to fully assess and support patients. Although the majority of returning military members have readjusted well to post-deployment life, one study showed that 44% reported difficulties after they return [77].

Military personnel returning from deployment are required to complete the Post-Deployment Health Assessment [78]. This medical screener is composed of 10 mental health questions and must be completed by a medical provider within 30 days of returning from military assignment [78]. In addition, the mental health departments in the Army and Navy use the Post-Deployment Psychological Screener, which consists of 22 questions assessing for symptoms for depression, PTSD, communication issues, interpersonal problems, alcohol abuse, and anger [78]. PTSD is commonly assessed due to the many distressing events that military personnel experience in combat. However, avoidance behaviors such as substance and alcohol abuse, withdrawing from others, and dissociating should be assessed as well [79].

During the post-deployment or reintegration phase, the service member returns, and the entire family is involved in helping him/her integrate back into the system [80]. There is usually a honeymoon phase, but awkwardness and tension often follow [81]. Family roles may have changed during this time, and the returning member will need time to adjust. For example, new parenting strategies may have surfaced in order to deal with being a "single parent" during the deployment. Upon homecoming, the military member should not expect family dynamics to have remained the same, but he/she may report feeling like a guest in his/her own home [82]. Some may not recognize their child, especially if the child was recently born or just an infant when they left. Similarly, children may not recognize the returning parent or express wariness of this returning stranger. As a result, the military parent may experience distress and hurt [83].

All health and mental health professionals involved in the care of veterans and their families should be committed to providing culturally competent and responsive care and should be engaged with available military resources. Referral to available resources is a vital part of the continuum of care for these patients. The military offers reintegration programs for veterans and their families. One such program is Coaching Into Care, a national telephone service (888-823-7458) of the VA created to help veterans, their family members, and other loved ones find the appropriate services at local VA facilities and/or in the community. It is staffed by licensed psychologists and social workers who can empower and support family members seeking to help veterans adjust to civilian life [68]. Military OneSource (https://www.militaryonesource.mil) is a free service provided by the Department of Defense to military members and their families to help with a broad range of concerns, including possible mental health problems. Peer support groups are also a useful tool. If a veteran and/or military family is living in an isolated area or lacks access to local VA services, the VA offers the Vet Center Call Center, a 24-hour call center staffed by combat veterans and family members of combat veterans.