A story on NPR earlier this week brought back some personal memories from nearly four decades ago. The subject of the report—related to the seasonal topic of New Year's resolutions—was the science of overcoming addictions and other undesirable behaviors. The piece began by discussing illicit drug use among U.S. troops in the Vietnam War, which was recognized at the time as so serious a problem that it stimulated a larger antidrug effort, with President Nixon appointing a drug czar and declaring drug abuse to be “public enemy number one in the United States.” As an army lieutenant during the last year of the war, I helped to run a replacement depot outside Saigon through which nearly all the remaining U.S. troops departed Vietnam. One of the principal parts of the processing was a urinalysis to identify heroin users, who were separated from the other troops and sent to a detoxification center. The proportion of users was disturbingly high. Nixon's drug czar, interviewed on the NPR report, said about 40 percent of enlisted men had tried heroin, and of those about half became addicted.

The good news about the drug use among the Vietnam veterans was that after they had been detoxified and returned to the United States, only about five percent of those who were addicted in Vietnam became re-addicted. This was a far lower relapse rate than for people who had acquired their initial drug addictions within the United States. The principal explanation offered for this finding is that environment and circumstances are all-important. Habitual behaviors are associated for each person with a particular environment or circumstance. For the soldiers who used heroin, that environment was the war in Vietnam. Once out of that environment, they had a much better chance of kicking the habit for good. So according to the NPR story, if you want, say, to stop smoking, don't linger in that area in front of your office-building's entrance where you and others have been accustomed to having a cigarette.

Other afflictions that Vietnam veterans brought home with them were more persistent than the drug abuse. Besides physical wounds, many suffered from what we have come to know as post-traumatic stress disorder. Although similar conditions had certainly been noted with veterans of earlier wars (some who had been in World War II were said to suffer from “shell shock”), recognition of this syndrome as a major effect of the Vietnam War was slow in coming. PTSD was not even defined as a distinct disorder until the 1980s, and it wasn't until a decade after the war that Congress mandated a comprehensive study of this and other problems among the Vietnam veterans. The PTSD was persistent. A later survey conducted fourteen years later found that the proportion of veterans still suffering symptoms of PTSD had barely changed from the earlier study.

Recognition of lingering problems of veterans, including especially PTSD, fortunately has been earlier and more complete with our most recent wars than it was with the Vietnam War. But the problems are no less serious, and no less chronic and lingering, for being recognized. Problems both invisible, including the psychological demons, and visible, including lost limbs, are long lasting or permanent and will be part of the legacy of the wars for decades to come.

The medical care and other economic costs entailed by that legacy are large and important in their own right, of course. They also can serve as a metaphor for the broader political and other consequences of our most recent wars. Those consequences include the short-term and the long-term, the visible and the invisible, the expected and the unexpected. Unexpected consequences of foreign wars are almost always numerous and extensive. They can be either positive or negative, although most of the unexpected results tend to be negative; what is planned for tends to be more what is wished for than what is feared. Anything close to a full balance sheet on the wars will be a long time in coming. People still argue about the balance sheet for the Vietnam War.