Q: What is your current thinking regarding the neural mechanisms underlying this flattened sensitivity to non-drug rewards?
A: Individuals with lesions to certain regions of their PFC, including the OFC, have difficulties in modifying behavior appropriately in response to altered reinforcement situations in their environment. Similarly, drug-addicted individuals also have PFC structural changes (e.g., reduced volumes), OFC and ACC functional changes (e.g., increased response when craving), and parallel behavioral changes (e.g., increased impulsivity). These findings led us to ask what role the OFC and ACC play in the drug-addicted individual’s ability to modify behavior based on the salience and value of a given reinforcer.
We think that drug addiction may be better understood as a disorder of neural regulation. Here’s why: even though the OFC and ACC are not sufficiently engaged in the processing of non-drug-related rewards, they are activated—in addicted individuals but not controls—in response to drug-related cues (e.g., words/pictures/videos of drug taking or pharmacologically similar drugs). Indeed, our preliminary fMRI results suggest that a possible communication breakdown between PFC sub-regions (OFC and dorsolateral PFC) may underlie the disrupted perception of motivational drive and the impaired control of behavior that characterized the drug-addicted individuals in our study.
Q: What does this work suggest in terms of clinical implications for treating drug addiction?
A: Consistent with the compulsive and chronically relapsing nature of drug addiction, our findings may help explain why efforts to control addiction through reinforcement can be compromised. It is possible that instead, efforts should be focused on devising new training and skill-development strategies and on supervised pharmacological interventions, all with the goal of decreasing the reinforcing effects of the drug, enhancing the relative value attributed to non-drug-related rewards, and increasing control of behavior.
Together, these approaches may enhance the ability to control drug-taking behavior even in situations when the desire for the drug exceeds that for other rewards.http://www.dana.org/news/
Among the different approaches for diagnosis, prevention, and treatment of drug addiction, exploring the evolutionary basis of addiction would provide us with better understanding since evolution, personality, behavior and drug abuse are tightly interlinked. It is our duty as scientists to explore the evolutionary basis and origins of drug addiction so as to uncover the underlying causes rather than continuing to solely focus on the physiological signs and global activity of this epidemic. Too often the treatment of addiction simply works to alleviate the symptoms of addiction, dealing with overcoming the physiological dependence and working through withdrawal symptoms as the body readjusts to a non-dependent state of homeostasis. However, we must not only concentrate on this aspect of addiction when considering global treatments and preventative programs. We must take into consideration that it is not purely the physiology of addiction we are battling.