Psychologists have long observed that people who have been neglected or abused tend to use drugs and alcohol. New research suggests that this may be in part because social stress spurs neurological changes that make drugs feel more rewarding, said Klaus Miczek, PhD, a Tufts University psychology professor and expert on the subject, who was invited to speak at APA's Annual Convention by APA's Board of Scientific Affairs.
Laying the foundation for this line of work was a 2002 study, published in Psychoneuroendocrinology (Vol. 27, No. 1). In it, McGill University's Michael Meaney, PhD, found that rats that had been separated from their mothers early in life showed a stronger response to cocaine as adults, becoming more hyperactive after cocaine administration than rats that had not endured separation stress. An ongoing animal study by Miczek and his colleagues had found clues as to why that is. Their research suggests that stressed rats — those that had recently been attacked — had elevated levels of dopamine in their prefrontal cortices. In addition to these transient changes, the brains of violence victims may undergo long-term, structural changes, including an increase in glutamate receptors, according to a study published this year in Psychopharmacology (Vol. 197, No. 2). Such a shift may account for dramatically elevated rates of cocaine use among rats in the study that had been victims of violence.
"The stressed ones take more, they take it faster, and they don't stop," Miczek said.