PTSD has a wide range of symptoms such as fear, depression, anxiety, anger, exhaustion, flashbacks and feelings of isolation.

PTSD has been widely researched in recent years since it has been recognized as a major problem within the military. But estimates of the prevalence rate of PTSD vary from five per cent to well over half of returning veterans. According to research by Milliken, Auchterlone and Hoge, 20.3% of active and 42.4% of reserve soldiers returning from Operation Iraqi Freedom (OIF) required mental health treatment. 

The majority, if not all of soldiers in Afghanistan and Iraq have experienced trauma. In recent research, 87% of returning soldiers said they had experienced incoming artillery, rocket or mortar fire. 74% had been attacked and 65% had seen dead bodies. 63% knew someone seriously injured or killed. 

U.S. Government Accountability Office has noticed in its report (Preliminary Findings on VA's Provision of Health Care Services to Women Veterans, GAO Testimony, Juyly 14, 2009) that female veteran patients are significantly different from male. "Almost all of these women are under the age of 40. 58 percent are between the ages of 20 and 29. VA data show that almost 20 percent of women veterans of OEF/OIF have been diagnosed with post-traumatic stress disorder (PTSD). Additionally, an alarming number of them have experienced sexual trauma while in military. As a result, many women veterans of OEF/OIF have complex physical and mental health care needs."

PTSD symptoms become noticeable often only months or years after service. In research on OIF veterans, soldiers reported more mental health problems in screenings more than half-a-year later from returning than immediately after coming home. Five times more veterans (about 20% of veterans) declared their relationship with family members was difficult by a later screening compared to immediately after return.

The military has been criticized for its treatment of female veterans. Female soldiers and veterans are more likely to be diagnosed with depression when they seek care for mental health symptoms. The men are diagnosed more often with PTSD.