The Neurobiological Driver of Cravings for Dirt and Other Drugs

APRIL 07, 2014
Steven P. Levine, MD

What do you crave: food, material possessions, love, attention, sex, sugar, chocolate, drugs, alcohol, praise, or power? For hundreds of thousands of people around the world, the answer is dirt. 
A few days ago, I came across an article on NPR about an upcoming documentary film called “Eat White Dirt.” The film focuses on the old yet current and not uncommon practice of eating white kaolin clay mined from places such as the southeastern United States.
This practice is a specific example of geophagy, the eating of earth, which in turn is an example of the broader phenomenon of pica, the eating of non-food substances. For some, the case of consuming white dirt may be culturally bound and passed down through generations, but for many others, it is a consequence of craving. 
The neurobiology of craving is highly complex, incompletely understood, and beyond the scope of this article. However, one need only to look at a craving for dirt in order to appreciate the existence of a biological driver for this bizarre practice that elicits such shame, confusion, and secrecy.
In many cases, a craving may reflect the body’s response to detecting deficiency in a vitamin or mineral. In others, such as overeating or substance addiction, this may be a false yet irresistible signal of need. In any case, most people have had some experience with a behavioral compulsion with motives that defy the capacity to articulate.
Enter the function of judging and shaming others for their cravings. It may be painful to recognize the “weakness” of acting upon cravings despite a sense of “wrongness” or the fear of judgment from others. A person may then consciously or unconsciously attempt to restore self-righteousness by condemning the “moral shortcomings” of others.
As Al Pacino’s character in the movie Scarface proclaims, “You need people like me so you can point your [expletive] fingers and say, ‘That's the bad guy.’ So, what that make you? Good? You're not good. You just know how to hide.”
Of course, not everyone feels subject to a craving or needs to either quietly or explicitly put someone else down in order to prop themselves up. However, it is natural to look at the differences in others to identify our own. Too often with addiction, this comparison is used as a foil to highlight our superior self-control.
That is what struck me so acutely regarding the practice of eating dirt. For all of the craved objects listed at the top of this article, there is an opportunity to focus on hedonistic indulgence. But because there is nothing obviously pleasurable about eating dirt, it is difficult to treat it so simply, and in our modern culture of germ warfare, it is particularly puzzling and shocking. 
There must be something else in our mind or body to explain it. With any addiction, take the time to understand the feelings surrounding the behavior, and you will find the anxiety that precedes the act, which may only be relieved once completed, and the shame and remorse that follow. This is why even when it looks like they are partying, most people in the grips of addiction are not having a great time. 
Those who crave dirt and feel ashamed may find comfort in the same submission to powerlessness recommended in 12-step recovery programs. Like other aspects of life, we are responsible for our behavior, but we may also be compelled to action by forces beyond our understanding and control. For those who are not, moving from Pacino to Jesus, “Let he who is without sin cast the first stone.”   

Steven P. Levine, MD, is a board-certified psychiatrist and therapist. He received his psychiatry training at New York Presbyterian Hospital and Memorial Sloan Kettering Cancer Center and currently practices in Princeton, NJ.

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