Cocaine, Genes, and Violent Behaviors

We studied a large sample of male children from birth to adulthood to determine why some children who are maltreated grow up to develop antisocial behavior, whereas others do not. A functional polymorphism in the gene encoding the neurotransmitter-metabolizing enzyme monoamine oxidase A (MAOA) was found to moderate the effect of maltreatment. Maltreated children with a genotype conferring high levels of MAOA expression were less likely to develop antisocial problems. These findings may partly explain why not all victims of maltreatment grow up to victimize others, and they provide epidemiological evidence that genotypes can moderate children's sensitivity to environmental insults. Show more

Cocaine produces its psychoactive and addictive effects primarily by acting on the brain’s limbic system, a set of interconnected regions that regulate pleasure and motivation. An initial, short-term effect—a buildup of the neurochemical dopamine—gives rise to euphoria and a desire to take the drug again. Researchers are seeking to understand how cocaine’s many longer term effects produce addiction’s persistent cravings and risk of relapse. In the author’s laboratory, work has focused on buildup of the genetic transcription factor ΔFosB. Levels of ΔFosB in the limbic system correlate with addiction-like behaviors in mice and may precipitate very long-lasting changes to nerve cell structure. Further pursuit of this and similar leads are first steps toward a complete understanding of the transition from cocaine abuse to addiction—and, ultimately, more effective treatments for those who are addicted. Show more