02/19/2011 04:56 pm ET | Updated May 25, 2011

Addiction's Secret Ingredient 'X'

In 1972, large numbers of combat troops began returning to the states from Vietnam, many of whom were dependent on heroin. Alarmed at the prospect of flooding a nation in the grip of a crime wave with lifelong addicts, President Nixon hired Lee Robbins, a leading light in psychiatric epidemiology, to study drug abuse among the returning soldiers. Lee Robbins studied 400 returning soldiers, all of whom reported themselves as addicted to heroin, all of whom shot, smoked or inhaled the drug on a regular basis and all of whom experienced physical withdrawal symptoms upon stopping use. In 1974, Lee Robbins published her surprising results. Two years later, only 12 percent of these soldiers continued to meet the study's criteria for addiction. 1

How do we square the notion of addiction as "a chronic, relapsing brain disease" with such overwhelming evidence of spontaneous recovery? And what caused 350 soldiers to use heroin compulsively in Vietnam and to stop when they returned to the states?

The secret ingredient X that is the sine qua non of addictive behaviors in humans has as much to do with the mind as it does with the brain: it is our sense of time. The addict trades feeling worse in the future for feeling better in the present, a bad deal made in order to override immediate, overwhelming emotions. Unsolved problems inevitably get worse, and the addict, by systematically falsifying with drugs, the feelings his body reports to his brain, gets worse at solving them. But he can always rely on the same desperate solution: He can operate directly on his emotions by taking more substances. Soon the solution is the problem. The future shrinks around the addict, measured in minutes and hours instead of days and years.

All humans tend to discount future over immediate rewards, choosing, say, $5 today over $10 next month. But this tendency, known in economic models of behavior as future or delay discounting, is far more pronounced in those who have patterned their lives around addictive behaviors. Among heroin users, studies have shown that the future discounting rates are about twice that of control participants.

So what might have happened to our troops in Vietnam to produce a state of temporary dependence on heroin? When faced with a threat to our immediate survival, we sacrifice reflection for speed of response. We do not dwell on our feelings in order to string the events around us into a narrative, but feel and act simultaneously. We remain oriented entirely to the moment. No one thinks about their college education during a firefight. In short, hostile, uncertain environments such as Vietnam, greatly increase our natural tendency to devalue the future. When our Vietnam veterans returned to the states, their sense of time opened up again. Feelings for family and career; "big picture" feelings gradually took precedence over immediate regulation of emotions, and heroin lost much of its draw.

But what about the 12 percent of soldiers in the study who continued to use heroin compulsively? Interestingly, the percentage corresponds almost exactly to the percentage of combat soldiers who experience significant symptoms of post-traumatic stress. In ordinary life, we recall sequences of events by re-experiencing in a mindful, minor-key way the emotions connecting them. Traumatic stress reactions cause us to relive, rather than remember our past horrors. We experience these horrors not as sequences in a narrative from which we emerge intact but in the same intense, uncertain, bodily way that we experienced them originally, and with a similar bias for the moment over the future. It is not surprising that between 25 percent and 50 percent of those who seek substance abuse treatment regularly experience intrusive thoughts, nightmares and somatosensory flashbacks around trauma cues.2 It may be that many of the veterans who continued to use heroin remained in the perpetual present tense of Vietnam.

How do those who struggle with symptoms of post-traumatic stress and those who battle a thirst for substances (often one and the same) widen their temporal horizons? By telling their stories. Functional MRIs have revealed that the same brain regions involved when one considers the past are activated when one projects into the future. 3 One must look backward to see forward. To accomplish this double process, one needs to be able to reflect on one's feelings, as all sequential recollections are glued together by an awareness of internal states. For an individual who has spent years suppressing emotions by taking drugs, it is useful to have the support of a reflective, elaborative listener who can provide some of the internal glue. It is no accident then that two mainstays of AA are the sharing of stories and the forming of mentoring relationships.

1. Robins, L. N., Helzer, J.E. Hesselbrock, M., & Wish, E. (1980). Vietnam veterans three years after Vietnam: How our study changed our view of heroin. In L. Brill, C. Winick (Eds.), Yearbook of substance use and abuse. New York: Human Science Press.

2. Marion Solomon, Daniel Siegel, Healing Trauma: Attachment, mind, body, and brain, W.W. Norton and Company: 1999.

3. Donna Rose Addisa, Alana T. Wonga, and Daniel L. Schactera, Department of Psychology, Harvard University, Cambridge, MA, United States MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, United States. Received 1 July 2006; revised 26 October 2006; accepted 27 October 2006.