Final answer:
The disorder that spurred the development of the DSM due to combat-related stress is post-traumatic stress disorder (PTSD) (option a). PTSD is an anxiety disorder that occurs after severe psychological trauma, which was prevalent among soldiers from World War II onward. The DSM was created in response to the realization of the need for a better understanding and management of mental health conditions suffered by combatants.
Step-by-step explanation:
The Diagnostic and Statistical Manual of Mental Disorders (DSM) was developed, in part, due to the recognition of combat-related stress and its link to mental disorders among soldiers during World War II. This malady is now known as post-traumatic stress disorder (PTSD), which is an anxiety disorder that emerges after experiencing intense psychological trauma. The development of the DSM arose out of a need to better understand and classify mental health conditions that were previously misunderstood or stigmatized, as seen in the reaction to soldiers' suffering from 'shell shock' during World War I and later battles.
Post-traumatic stress disorder was common among American GIs during the Vietnam War but was not adequately diagnosed or treated by the Veterans Administration. The psychological trauma that these veterans faced was, back then, often mischaracterized as a sign of weakness or 'hysteria' within the military and society. It took substantial time for the medical community to properly acknowledge the gravity of PTSD and to provide the appropriate treatment and support for those affected.
Before the formulation of the DSM, soldiers were frequently denied the necessary mental healthcare, and were stigmatized for their inability to adjust. With the influences from both World Wars and subsequent conflicts, the recognition that psychological trauma needed serious attention led to advancements in diagnosing psychological disorders. Hence, the DSM was developed to provide a comprehensive guide for diagnosing and treating such disorders.