What's the first thing that comes to mind when you hear the word disease? You might think of cancer, diabetes, or epilepsy. But do you think of drug abuse? Probably not. But, for some people, drug abuse can lead to a disease called addiction.
A disease is when something in the body doesn't work like it's supposed to-an organ or a whole system has something wrong with it and disrupts functioning. Diseases can be caused by many different factors, from your genes (what you inherited from your parents) to germs and viruses to not getting the vitamins that your body needs to stay healthy.
Some diseases can be cured with medication or changes in lifestyle and may never come back. Others are chronic diseases, meaning they last for a long time or can come back again.
Addiction is a chronic disease. Drugs change the way the brain works, and using them can lead to addiction. Once a person is addicted to a drug, they feel the need to take that drug over and over just to feel like their "normal" self. Tracking down and taking the drug usually becomes more important than eating, sleeping, dating, doing school work, or earning money.
Even if they stop using drugs, people with addiction have brains that have been chemically altered, making them vulnerable to relapse (resuming drug use).
To learn more, take a look at The Science of Addiction. Share something you didn't know before.
Your school probably has science classes like biology and chemistry and maybe even ecology, but does it offer a class specifically on neuroscience?
Neuroscience is a branch of biology that focuses on the body’s nervous system—which includes the spinal cord, nerves, neurons (nerve cells) and, of course, the all-important brain.
Work in the neuroscience field is varied and exciting. Neuroscientists might study how messages travel from one area of the brain to the other, or they might focus on how the brain is involved in behavior and decision-making.
Still others might work to find causes of and cures for diseases and medical problems like stroke, Parkinson’s disease, depression, Alzheimer’s disease, schizophrenia, and addiction.
At NIDA, research focuses heavily on neuroscience, considering that drug addiction is a brain disease. Without neuroscientists and the research they do, we would be unaware of some pretty important things—like how the brain isn’t fully developed until a person is well into their 20s and how drugs like marijuana affect the teen brain differently than an adult brain.
So much about the brain is still unknown. That makes neuroscience a particularly exciting field. If you are interested in help shed light on the mysteries of the brain, consider exploring neuroscience as a career. Check out the advice NIDA scientists offered to SBB for teens interested in a future career in science.
Learn more about the brain from these NIDA resources:
You may think you know what addiction is—lots of people have many different opinions about addiction and different ways of defining it. Here are some myths you may have heard:
- Getting over addiction to drugs is a choice.
- In order for treatment to work, the person has to hit “rock bottom.”
- People have to choose to get treatment or it won’t be effective, such as when a judge sends a person to treatment facility instead of jail.
The truth is that addiction is a complex brain disease that scientists are still figuring out. For instance, one person may use a drug once or many times and nothing bad happens, while others may overdose with the first use. Some people use drugs regularly and never become addicted, while others try drugs once or twice and do become addicted. There is no way of knowing in advance how a person may react to these dangerous substances. Whether or how quickly addiction takes hold in individuals depends on many factors, including:
- Genes: Research shows that some people’s genes may leave them more susceptible to addiction than other people’s.
- Environment: Kids who are exposed to drug use in their families or neighborhoods are at greater risk of engaging in drug abuse themselves.
- Age at first use: The younger a person uses drugs, the more vulnerable he or she is to addiction in adulthood. Since the brain continues to develop well into a person’s twenties, using drugs in the teen years can set a person up for later drug problems.
What scientists know for sure is that many drugs “turn on” the brain’s reward circuit, which is part of the limbic system. The person then learns to associate the drug with pleasure and starts to crave it more and more, leading to compulsive drug use and often to addiction. In an addicted person, the brain changes in ways that cause compulsive drug seeking and use, despite negative consequences, so even if they want to quit, they can’t without treatment and support. That’s why addiction is considered a brain disease. Other activities in life also activate the brain’s reward circuit and can cause “driven” behaviors, such as compulsive overeating or video game playing. However, scientists are still trying to figure out why this happens in non-drug contexts—it may be connected to dopamine levels in the brain. Learn more about the science behind drug addiction by visiting http://nida.nih.gov/scienceofaddiction/.
SBB has talked a lot about how drug addiction is a complicated brain disease. But it’s not the only one. Obesity also involves the brain and is the subject of an HBO special that takes a serious look at this complex problem. The 4-hour documentary series “The Weight of the Nation” covered everything from fatty liver disease in overweight children to how humans are wired to find pleasure in food to how our food supply has changed over the years. If you missed it in mid-May, you can go to HBO’s Web site and see it for free. To get a better idea of the obesity problem, check out this creative infographic, “Obesity: Complex But Conquerable,” from the Institute of Medicine. Our Brains: Wired To Find Pleasure in Food You may see overweight people and wonder, “Why don’t they just stop eating so much?” If the solution were that simple, then nearly two-thirds of the U.S. population would not be either overweight or obese. NIDA Director Nora D. Volkow, M.D., spoke in the HBO series about how brain science relates to obesity. She noted how early in human civilization, when a person’s survival depended on the ability to hunt and gather, our brains associated tasty food, like bananas, with pleasure, making it more likely that a person would climb a tree to get the fruit. Today, that powerful connection still exists between food and pleasure, except now we don’t have to work so hard for our food. For some people, the rush of dopamine associated with eating a food they like may cause them to overeat impulsively—a brain reaction they cannot control, according to Dr. Volkow. It is a similar response to what happens in drug addiction when people compulsively seek and use drugs despite the negative consequences. Nature AND Nurture The documentary emphasized that our society—with its overabundance of fast food restaurants, massive portion sizes, and schools serving foods like French fries and pizza—makes it easy for people to make poor food choices. To reverse this bad health trend, we need to change our environment and make better choices. Our stomachs, livers, and hearts aren’t the only organs affected by obesity—the brain also takes a hit. Dr. Volkow said, “Obesity negatively affects the function of the brain. The greater the problem of obesity, the less activity in areas of the brain that are extremely important for cognitive (thinking) operations.” Find out more about what other experts from the National Institutes of Health had to say about obesity, and preview a clip from the documentary:
Hello, you last heard from me when I won one of NIDA’s Science of Addiction Awards at the Intel Science and Engineering Fair. Since then, NIDA invited me to become an intern at its Intramural Research Program (IRP) lab in Baltimore, Maryland, and it was a memorable experience. I worked in the Molecular Targets and Medications Discovery Branch. The research I conducted at NIDA focused on cocaine addiction but also has applications for Parkinson’s disease and schizophrenia.
My project looked at how dopamine receptors in the brain might structurally combine to affect cocaine addiction and other neurological disorders. After taking two buses to come to the IRP campus every morning, I strapped on my gloves and started preparing the substance to give to the dopamine cells. My experiments usually lasted the whole day. I always waited with excitement at the end of the day to see the results. Through the experimentation, we developed a better understanding of the intracellular signaling of dopamine receptors (how they “talk” to each other), which could eventually help in developing new drugs to treat ailments associated with the dopamine receptors, including addiction.
I enjoyed the opportunity to work in a professional environment. I was able to contribute to the research in Dr. Sergi Ferre's lab, called the Central Nervous System Receptor-Receptor Interactions Unit. Every Thursday, our lab met to discuss our results. There, I had the amazing opportunity to work with my mentor, Dr. Xavier Guitart—something I will never forget. I was new to this specific field of neurology, so Dr. Guitart guided me through the whole process. He was always there when I needed guidance. It was so great to work in such a supportive environment.
Loss Led to Interest in Brain Science
I became interested in drug addiction because of my strong desire to contribute to research in the neurology field, after my uncle passed away from stroke in 2008. Stroke constricts blood flow to the brain, which is why it is a neurological disorder. Addiction is another disorder that affects the brain, which is what initially made me interested in drug addiction. My hope is that developing a treatment for addiction will also shed light on neurological disorders like stroke.
I've always wanted to be a medical doctor, possibly a surgeon. But now that I've had a glimpse of working in a research lab, it is something that I want to pursue later in life. Through this opportunity, I’ve learned that drug addiction is an important issue that affects many people, and that my efforts, along with many others’ efforts, will contribute to finding effective treatments. Working at the NIDA lab gave me a lot to think about as I enter my final year of high school.
Yamini Naidu is a senior at Valley Catholic High School in Beaverton, Oregon. Her lab work in NIDA's Intramural Research Program has inspired her to pursue a joint M.D.-Ph.D. program in neurology.
I remember my sophomore year in high school, feeling a life-changing moment of excitement when I read Dr. Karl Diesseroth’s work on optogenetics, a new field that involves studying the brain with light. I could never have imagined it would mark the beginning of a journey that would lead to presenting my research to NIDA Director Dr. Nora Volkow and her colleagues just 2 years later.
Along my journey, I was fortunate to have wonderful mentors from Yale University who truly cared about my interests. Professors Amy Arnsten and Ralph DiLeone are brilliant leaders in neuroscience research, yet they still found time to generously mentor. I performed optogenetics research in Dr. DiLeone’s laboratory, working closely with postdoctoral fellow Dr. Benjamin Land, who is a great, generous mentor.
Shedding Light on Connections Between Brain and Behavior
With optogenetics, light-sensitive chemicals (first discovered in algae) are inserted into the DNA of specific cells, giving us the ability to control those cells. In the project I worked on, we used this method to modify particular neurons in the prefrontal cortex of genetically altered mice. The prefrontal cortex is a region involved in regulating behavior and self-control.
We delivered blue laser light via fiber optics to the animals’ prefrontal cortex to control the timing of their behavior. This approach suggested a whole new way the brain could be repaired effectively, using light to target specific areas causing the trouble—instead of using medications that could affect the whole brain. By pairing genetics with light, optogenetics allows us to design new ways to repair the brain in people with brain disorders.
Undertaking such research felt especially compelling to me because of my desire to help people with difficulties stemming from disorders affecting their prefrontal cortex. Millions of individuals suffer from such disorders, which include drug addictions, schizophrenia, depression, Alzheimer’s disease, and Parkinson’s disease. These conditions might be better managed or even cured in the future with new treatments growing out of optogenetic research.
Sharing My Research and My Passion
As a result of these experiences, I’ve presented my research many times to different audiences. I have talked to students from elementary through high school, participated in Connecticut state science competitions, presented at a regional competition at the Massachusetts Institute of Technology and then at the George Washington University as a national finalist in the Siemens Competition in Math, Science, and Engineering, at the American Academy of Neurology, and finally at the Intel International Science and Engineering Fair, where I received the NIDA Addiction Science Fair Award. Presenting to Dr. Volkow and her colleagues proved to be one of the greatest opportunities. I loved responding to their rapid-fire questions after giving my presentation. I also had the chance to tour the National Institutes of Health campus and Intramural Research Program laboratories.
Winning this award offered me a window to seeing the best translational research in action—applying what we learn from basic research to develop treatments and then try them out in clinical trials. It seems there are no limits to the questions that could be imagined and tested and the scientific inquiry that could be accomplished on the road ahead.
John Solder is currently a freshman at Yale University. The optogenetics project he worked on is part of a manuscript he co-authored, to be published in the Proceedings of the National Academy of Sciences (PNAS). He will be continuing research in this area.
When our brains are healthy, we barely notice this marvel of engineering that controls our every thought, feeling, and move. But the many people suffering from brain disorders, including addiction, know that malfunctions in the brain can change who we are and how we manage our lives.
For a closer look into how our brains function—or malfunction—scientists have discovered a new way to turn individual neurons and cell circuits on and off using light.
Neurons in the brain pass electrical impulses back and forth thousands of times a minute, but turning them on and off isn’t quite as simple as flipping a light switch. First, researchers have to insert light-sensitive genes, taken from algae, into specific neurons. Then, using lasers connected to thin fiber optic threads, they can activate or deactivate the modified cells to see how neurons or groups of neurons work together. So far, this new field of optogenetics research is limited to animal studies.
Working To Understand Brain Disorders
Scientists have successfully switched mouse neurons on and off to see how different brain circuits control habits, emotions, and behaviors. The technique may also help scientists understand the causes and potential treatment of specific brain disorders such as schizophrenia.
Optogenetics is also helping scientists understand how addiction affects the brain.
Researchers at the Massachusetts Institute of Technology trained mice to run through a maze for a chocolate reward. Out of habit, the mice continued to run through the maze even after the reward was no longer present. But by using optogenetics to activate cells of a brain area called the basal ganglia, the researchers turned off the chocolate-chasing habit. (The basal ganglia contain the brain’s reward circuits, which are involved in addictions.)
Scientists are hopeful that optogenetics could eventually help treat addiction and other neurological conditions in people.
Watch this video to learn more about optogenetics: