Many wars have been fought during the history of civilization. About 30 armed conflicts are occurring now around the globe involving more than 25 countries. Many war veterans have symptoms of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) including suicidal ideation and behavior. PTSD is frequently comorbid with MDD. I have previously proposed that some or all individuals diagnosed with comorbid PTSD and MDD have a separate psychobiological condition that can be termed "posttraumatic mood disorder" (PTMD). This idea was based on the fact that a significant number of studies suggested that patients suffering from comorbid PTSD and MDD differed clinically and biologically from individuals with PTSD alone or MDD alone. Individuals with comorbid PTSD and MDD are characterized by greater severity of symptoms, increased suicidality and the higher level of impairment in social and occupational functioning compared to individuals with PTSD alone or MDD alone. Neurobiological evidence supporting the concept of PTMD includes the findings from neuroendocrine challenge, cerebrospinal fluid, neuroimaging, sleep and other studies. In this paper, I propose a model of suicidal behavior in war veterans with PTMD. The model consists of the following components: (1) genetic factors; (2) prenatal development; (3) biological and psychosocial influences from birth to mobilization/deployment; (4) mobilization/pre-deployment stress; (5) combat stress, traumatic brain injury, and physical injury; (6) post-deployment stress; (7) biological and psychosocial influences after the deployment; (8) trigger (precipitant) of a suicidal act; and (9) suicidal act. The first four components determine vulnerability to combat stress. The first seven components determine predisposition to suicidal behavior, a key element that differentiates PTMD patients who are at high risk from those at lower risk. Suicidal behavior in PTMD can be attributed to the coincidence of a trigger with a predisposition for suicidal behavior. Suicide prevention in war veterans with PTMD should focus on (1) improvement in recognition of PTMD; (2) treating symptoms of PTMD; (3) preventing a relapse when the patient is in remission; (4) treating suicidal ideation; (5) treating comorbid psychiatric conditions including alcohol and drug abuse; (6) treating medical and neurological disorders including traumatic brain injury; and (7) social support. It is extremely important to understand PTMD, to optimize assessment and treatment for people with PTMD, and to identify processes that facilitate recovery from exposure to traumatic events. Every nation, every generation, faces traumas that cause suicide. The world needs to deal with this and it is one thing that the world can come together on.