Addiction, Withdrawal, and the Brain

Brain activity is necessary for all human activity, making it the most complex organ in the entire human body. The brain coordinates involuntary actions such as heart rate, breathing and sleeping as well as voluntary behavior like movement and emotional regulation. In short, the brain has a lot of responsibilities, which include regulating basic bodily functions, interpreting and responding to one’s surroundings, and shaping human emotions, thoughts, and behavior. (

However, some things can interfere with regular brain activity. The most common brain-altering substances are a variety of drugs, and they are known to change the way nerves and neurons send, receive, and process information normally. This chemical interference can be useful at times; for instance, consider the use of pain killers that regulate sensory overload following a surgery. However, when drugs are abused, the negative impact on the brain can be quite significant.

According to The National Institute on Drug Abuse, drugs affect the brain by tapping into their communication system. Drugs such as marijuana and heroin are very similar in structure to the neurotransmitters that are produced naturally by the brain, therefore they can trick the cell’s receptors into allowing them to attach to the cell. These impostors do not activate the cells in the same way as the natural neurotransmitter and the end result is that abnormal messages are broadcast throughout the entire central nervous system.

Other drugs such as cocaine and amphetamines cause neurons to release excessive amounts of neurotransmitters or they prevent the normal recycling of these natural chemicals. As these drugs trick the brain’s communication system, the natural neurotransmitter dopamine begins to flood the body in abnormal amounts, resulting in the “high” that drug users experience. The body then begins to crave more of the substance that brings it pleasure, which often results in an addiction.

So, what happens to the brain when a person decides to stop using the drug that he is addicted to? Research suggests that over time drug abuse alters the body’s physiological and chemical baseline. This imbalance causes the brain to overproduce or under produce natural neurotransmitters. However, when the drug is no longer present in one’s system, the brain continues to function at this imbalanced level, contributing to the negative withdrawal symptoms. The body eventually readjusts itself, however this process can take anywhere from several days to several weeks.

First it is important to understand the concept of drug tolerance. After repeated drug binges, the brain begins to reduce the production of dopamine and the number of cellular receptors in an effort to control the surge of dopamine in the body. Consequently, the drug user will need to use more and more drugs to continue to experience the high. This is known as tolerance. However, when a person decides to stop using drugs, for a while the brain continues to function as if the drugs are still present, which results in the unpleasant side effects that are experienced during withdrawal. During withdrawal, the brain continues to under-produce natural chemicals until the brain is able to reset to its regular functions.

Alternatively, drug use may signal the brain to produce more of the body’s natural chemicals to ensure survival. For example, neurons in the base of the brain produce the chemical noradrenaline (NA) which stimulates life-sustaining activities such as breathing, wakefulness, blood pressure, general alertness, and other functions. However, opioid use suppresses these neurons, resulting in drowsiness, low blood pressure, among other symptoms. Over time, the brain produces more NA to compensate for the suppression effects of the drug. However, when opioids are no longer present in the body, the brain will continue to release excessive amounts of the NA chemical until it readjusts itself. ( This imbalance results in the person experiencing withdrawal symptoms such as jitters, diarrhea, and muscle cramps.

There are some medications that can assist with lessening withdrawal symptoms so it is important that you talk to a doctor if you or someone you know is ready to break an addiction.


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