This is a great article on why some people get addicted to drugs and alcohol when the majority of people who experiment with drugs do not. In short, addicts tend to have fewer D2 receptors, thereby reducing the reward they experience from common, pleasurable experiences. People who produce fewer D2 receptors also tend to gain more weight and be more susceptible to food reward. As both articles explain, for these individuals there is a reward-deficit in daily life that is often filled with substances and food. Everyone gets stressed or depressed or anxious and it is common for the average person to turn to rewarding food or alcohol or even illicit drugs to adjust their mood. What's interesting is how these acts become habits which become addictions.

It is fairly evident that an individual's environment plays a large role in their decision to use alcohol, food, or drugs to produce a sufficient reward (for lack of a better term). For instance, attorneys typically have higher rates of substance abuse and depression than the general population. Are people with low D2 signaling drawn to the practice of law? Probably not. Accordingly, it is clear that changes in environment have the potential to change a person's substance abuse behavior.

How does this go back to food reward (as everything I blog about must)? Last summer, I was studying for the bar exam. I was a ball of anxiety, but I still worked out three times a week. I also gained somewhere in the ballpark of 10 or more pounds. Sure, my stress probably led to high cortisol levels, but it also led me to eat a metric ton of jelly beans and snack mixes and anything else convenient and instantly rewarding. I rarely cooked and rarely ate out at restaurants.

This summer, I am working and have my nights and weekends to myself. I lost a decent amount of weight and my clothes fit better. Did the bar exam change my brain? No. It was a temporary environmental influence on my D2 receptors and led me to find external reward mechanisms. In short, at least part of our obesity epidemic is fueled by environmental factors, such as the convenience of fast food, the opinions and influences of those around us, and the stresses of daily life. Let's be honest, there is a documented direct correlation with the number of fast food commercials aimed at children at rates of childhood obesity. Or, as the NY Times article at the top of this post so eloquently put it "Even people who aren’t wired for addiction can become dependent on drugs and alcohol if they are constantly exposed to them, studies have found."