The results of a new study, which have been published in Molecular Psychiatry, show that a portion of the brain’s reward system is blunted when a person becomes addicted to alcohol. This effect continues even after long periods of abstinence.
The researcher’s findings demonstrate that those living with an addiction to alcohol release fewer endorphins in their brain when compared to a control group. The new study found similar results to a previous study performed by the team, which looked at gambling addicts’ endorphin levels.
How are Endorphins Affected by Alcohol?
Endorphins are the body’s “feel good” chemical messengers. They are released when we engage in enjoyable activities, such as listening to music, eating chocolate or playing with a pet. Physical activity also causes the brain to release endorphins.
The researchers used Positron Emission Tomography (PET), a specialized type of scan that shows the chemical messengers’ movements. Their goal was to increase understanding of how the brain’s endorphins change with alcohol addiction.
Study Participants had History of Alcohol Abuse
Thirteen people with alcohol abuse issues, who weren’t drinking at the time of the study, underwent PET scans. One scan was taken before and one after receiving a small dose of the ADD medication dexamphetamine to stimulate their endorphin system. The control group for the study was 15 people who didn’t have a history of addiction.
The group with alcohol abuse issues released “significantly less endorphins” than the control group. The reduced level of endorphins didn’t change, even after long periods of time without drinking alcohol.
First Time Lower Endorphin Release Linked to Alcohol Addiction
This is the first time that lower endorphin release has been shown in people with alcohol addiction. The findings are similar to an earlier study conducted on participants with a history of gambling addiction, which suggests that low endorphin production is something common to those living with other addictions.
The study results didn’t indicate whether this dysfunction of the brain’s reward system is a result of the addiction or was present before the addiction took hold. The researchers are also unclear whether lower endorphins are present in people who are at higher risk for developing an addiction.
Research has shown that drug addiction is a chronic disease affecting approximately 21.5 million people in the US. The exact causes are complicated, and at present it’s impossible to predict exactly what leads someone to become addicted to a drug. With repeated exposure to an addictive drug, changes occur in the brain that continue the cycle of addiction.
Addiction interferes with the reward processing circuits in the brain. A brain under the influence of an addictive drug receives a massive amount of the neurotransmitter dopamine.
What is Dopamine?
Dopamine is a chemical that behaves like a messenger between brain cells. It helps to determine how we learn, what we eat, how we move and whether we become addicts. Dopamine also helps with motivation to repeat a particular action, such as doing something pleasurable again.
Drugs like heroin, cocaine and even nicotine cause the brain to release large amount of dopamine. When the brain gets too much of this neurotransmitter from drugs, the person with a substance abuse problem continues to look for a “high” from the drug. Other pleasurable experiences like eating an ice cream cone or watching a funny movie won’t be enough to give the brain the amount of good feeling it needs.
TMS Targets Brain’s Neural Circuits
For this reason, addiction is called a brain disease. Until now, researchers, haven’t been able to find treatments targeting the neural circuits. Researchers at the Medical University of South Carolina (Charleston) have discovered a treatment that targets them.
The researchers, who supervised by Colleen Hanlon, Ph.D., used transcranial magnetic stimulation (TMS) to dull the brain’s response to wanting to consume cocaine and alcohol in chronic users. This noninvasive brain stimulation technique was used in two groups of participants, and their reactions to receiving either a real treatment or a sham one. Their reactions were recorded, and the results showed “no significant interaction with region of interest [in the brain] for either experiment.”
The findings were published in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.
A cocaine addiction is much different than an opioid addiction, and not just because the two drugs provide very different types of highs. A person who is addicted to opioids, such as heroin or prescription painkillers, often has a very difficult time getting over the physical withdrawal symptoms, which often lead the addict back to using opioids. These withdrawal symptoms can be extremely painful and usually last 5 – 10 days or more, depending on the severity of the addiction. However, a cocaine addict has a different obstacle to overcome.
While there are fewer physical withdrawal symptoms associated with cocaine addiction, there is a significant emotional withdrawal that takes place, and lasts much longer than the physical discomforts of an opioid addiction. And, according to new research, this emotional dependence occurs in the brain much earlier than previously expected.
“The study provides evidence that some of the characteristic brain signals in people who have developed addictions are also present much earlier than most of us would have imagined,” explained Marco Leyton, a professor at McGill University and an expert on drug use and addictions.
Researchers at the university gathered recreational (not considered to have an addiction) cocaine users and had them use the drug with a friend that they had previously used with before. The sessions were videoed and then later played back to the subjects. When the subject was viewing the footage the researchers were also measuring their brain waves. They found that when the subject viewed their friend using cocaine the brain released far more dopamine than before and also indicators that cravings were more severe. This information points to recreational users who may not have as much control over their drug use as they may have thought.
This information is vital because it helps to open a discussion on recreational drug usage, especially having to do with cocaine. This extremely addictive drug is often used in party situations, and some people report occasionally using the drug, but do not consider themselves addicted. However, this new information likely shows that they may be more addicted than they thought.
Genetics may Define Risks of Addiction
A new study conducted by a group of researchers may shed light onto why people get addicted and how to locate individuals that may be susceptible to addiction before they ever use drugs. This groundbreaking discovery is unique because the researchers were able to study the brain before and after drug addiction set in in rats that were engineered to be prone to addiction. The hope is that future generations will be able to get screened for the presence of addiction genes prior to drug or alcohol use, therefore preventing a potentially deadly addiction. This is especially important of late, given the high rate of overdose deaths in our country currently.
In order to conduct the study, researchers genetically modified rats to either be high responders (more likely to become addicted) or low responders (less likely to become addicted). The genetically modified rats were then studied prior to the introduction of cocaine. This was a first for scientists. While it was understood prior to the study that humans who were addicted to drugs had different chemical reactions in their brains, it was difficult to study this phenomenon prior to addiction setting in. With the ability to study the rats before an addiction began scientists could locate key indicators of the makeup in the brain, thus allowing for future screenings to be developed for humans.
“There’s a number of essays that could be created to look at these different molecules to identify if somebody has a history of addiction in their family. If they have certain low versus high levels of one of these molecules, then they can be a candidate for treatment to prevent addiction in the first place. Or, if we know that they’re an addict, to prevent relapse,” explained Shelly B. Flagel, Ph.D., the study’s lead author.
Results of the rat study show that rats who were more likely to become addicted to cocaine had a higher level of fibroblast growth factor, which remained high after the rats were addicted to cocaine. These rats also had lower than normal dopamine D2 receptors. More studies will need to be conducted, but researchers are pleased that they are able to now study addiction-prone brains before an addiction sets in.