There’s promising evidence that some mental and emotional disorders—such as anxiety, depression, and substance use—can be prevented, especially if action is taken early in life.

The majority readjust to life off the battlefield with few difficulties. But a significant number—44% who’ve served in Iraq and Afghanistan, according to one survey—say they’ve had problems readjusting after their return.

Multiple reasons. For one, it costs a lot for biopharmaceutical companies to research and develop new medications.