Joanna Fowler: What our images show is that addiction is really a disease of the brain and not a moral weakness.
Joanna Fowler is a chemist at Brookhaven National Laboratory and winner of the prestigious 2009 National Medal of Science. She studies the chemistry of drug addiction using what are called tracers – radioactive molecules attached to minute quantities of drugs such as cocaine.
Joanna Fowler: For example, we can put a carbon 11 atom in a drug molecule and use it to image where the drug goes or how long it stays in the brain.
Fowler said that all the drugs humans abuse activate what she called the ‘reward’ center, located deep inside every brain. She said that this ‘reward’ center is essentially the system that gives us a sense of well-being.
Joanna Fowler: Cocaine addicts, alcohol abusers, meth abusers – all of these show an understimulated reward system. So we think that what’s going on in addiction is that people who are addicted do not have the same pleasures at natural reinforcers like food, so they take drugs to compensate.
In other words, their ‘reward’ centers aren’t functioning well, so they seek the extraordinary stimulation of a drug high. Fowler also found that, in addicts, the brain’s frontal cortex is less active than in a typical brain.
Joanna Fowler: It’s the part of the brain that allows you to terminate behavior and anticipate consequences of behavior.
She explained what she sees when she looks at Positron emission tomography or PET scans, which is the machine she uses to monitor the activity of her radioactive tracers. PET is a nuclear medicine imaging technique which has the capacity to create a three-dimensional image of the internal workings of the body.
Joanna Fowler: So the reward center in a non-addicted brain – say you use a rainbow colored scale – the parts of the brain which are the reward center would be red, and say an addicted brain would be tending down toward orange or yellow.
In other words, she said, there’s a 20-30% decrease in function in the elements of the reward system. She said this helped illustrate the appeal of drugs to someone with a low-functioning reward system.
Joanna Fowler: All of the drugs that are abused by humans release a huge amount of dopamine in the brain, and this causes a very large stimulation, and we think this is what brings about the high. Drugs are just a very, very powerful stimulator of the reward system.
She said the same things happen in the brain of compulsive overeaters as drug addicts.
Beth Lebwohl researches, writes and helps produce science content in audio and video formats for EarthSky. She is one of the authors on EarthSky.org, a script-writer for our podcasts, and helps host our English science podcasts in 90-second, 8-minute and 22-minute formats. Beth came to EarthSky in 2006 from the American Museum of Natural History's Department of Astrophysics, where she was surrounded by some of the greatest telescope-building, equation-wielding, code-writing physicists of our time. And they made her think . . . this science thing . . . it's pretty cool.