Understanding Serotonin and Drug use

brain to represent serotonin and how drug use affects it

Table of Contents

How Neurotransmitters Work

When the brain receives any information, neurotransmitters are the vehicle for the mechanism of processing that information. For example, when you read this sentence on your phone or computer, your eyes process the words you see and convert them into information.

This information is passed to the visual processing part of the brain through brain cells called neurons. Once the information is processed in the visual part of the brain, the meaning is applied to what you see via memory.

For information to pass from one neuron to the next, it must cross the gap between neurons called a synapse. When neurons cross the synapse, the information becomes a chemical signal. These chemical signals travel in synapses or neurotransmitters. The brain consists of 86 billion neurons, so it is capable of a lot of information processing.

How neurotransmitters pass between neurons is essential to the functioning of the brain. The chemicals used in neurotransmission inform how we experience and interpret our environment.

Computers make a good analogy for brain function; electrical currents travel between a network of circuits, and the direction of the current, the amount of current, and where the current ends up creates the computer’s resulting output.

Information in the brain is passed between neurons using its form of electricity and the chemicals called neurotransmitters. The amount and type of these signals and the different paths they take through the brain create what we think, feel, and react to stimuli.

Drug Use Affects Neurotransmission

During normal brain function in a sober individual, the release, breakup, and reabsorption of the chemicals that make up neurotransmission happens on a regular cycle within certain parameters.

When a user introduces a drug into their system, an abnormal process takes place. This abnormal process is why people feel high and have an altered state of consciousness while using; the brain is experiencing something it normally couldn’t experience on its own due to the checks and balances on neurotransmission that usually occur in the brain.

When you first start using drugs, the wacky effects the drugs cause on neurotransmission wear off after a certain period, and the brain’s signals return to normal. The signals normalizing are the cause of the process of sobering up or of feeling less intoxicated.

After the brain has experienced this enough or has by force worked beyond its baseline parameters, the structure and function of neurotransmission changes.  The parameters for the number of neurotransmitters permitted in synapses are affected semi-permanently.

This change in the brain’s default neurotransmitter expectation in synapses is what creates drug tolerance. A user will have to take more of the drug, flooding more chemicals into the brain, to meet the now widened parameters of good neurotransmitters.

While a hit of drugs equivalent to the first time used still creates the same number of chemicals, the brain doesn’t register them as a dramatic increase anymore, so the person doesn’t become as intoxicated.

Withdrawal occurs when the altered neurotransmission parameters do not achieve the same effect due to the cessation of substances. The brain has become acclimated to the increased levels of chemicals and needs them to feel normal. Quitting substances makes the brain feel like it doesn’t have enough of its normal chemicals because of the number of chemicals it has become used to artificial alteration.

The need for more drugs to feel high and drug cravings are the key components of addiction.

Drugs Replace Neurotransmitters

As long-term drug abuse continues after the above situations have occurred, the brain continues to alter itself in the presence of drugs. The actual structure of the cells begins to change in response to the massive levels of neurotransmitters present; the cell shuts itself off from being affected dramatically by fluctuating neurotransmitter levels by reducing the number of receptors present to accept the messages of neurotransmission.

Take a drug that causes the brain to be flooded with serotonin frequently. The brain will respond to these massive surges by reducing serotonin receptors, so the brain is less affected by the increased quantity of serotonin. While this mechanism protects the brain from drugs, it causes drug dependence and addiction.

The brain becomes acclimated to increased serotonin levels, and natural occurrences during sobriety that result in serotonin production do not feel good to the user anymore. Each type of drug affects a different cocktail of neurotransmitters, so different drugs have different highs. Drugs that affect serotonin are feel-good drugs that make you feel joyful.

Why Serotonin is Important to Mood

Serotonin is composed of amino acids and creates them in the central nervous system. It is a product of Tryptophan, an amino acid we get through food consumption. People take Tryptophan for a huge variety of physiological processes, like intestinal functioning, sex, and staving off depression.

Serotonin is most famous for its involvement with obsessive-compulsive disorder, depression, and anxiety due to the studies over the last few decades on these topics that became widely circulated. There is an entire class of drugs related to manipulating serotonin called “SSRIs,” or selective serotonin reuptake inhibitors. These drugs create more receptors on neurons for serotonin, so more of the natural serotonin produced by the body is received and processed by neurons. Famous SSRIs include Zoloft and Prozac.

When someone begins suffering from a clinical disorder related to anxiety and depression during drug and alcohol withdrawal, it’s because their body acclimates to the serotonin released during drug use.

During withdrawal, users of various serotonin-altering substances experience heightened irritability, sleep irregularities, severe anxiety, problems with concentration, and symptoms of mental health conditions like bipolar disorder.

Drugs, Serotonin and Impulsivity

Impulse control is deeply related to addiction for a variety of reasons. It is well known through research that a relationship between addiction and impulse control exists, in that those with less ability to control their impulses are more prone to addictive behaviors and lifestyles. Someone who is more impulsive while sober is more inclined to develop a substance abuse problem.

Serotonin is one of the brain’s tools for directing impulsivity, and thus in the role addiction plays in an addict’s life. While the exact mechanism is not well understood, the implications of impulsivity on the recovery process are well observed.

For example, users with a cocaine addiction generally are more prone to impulsive decision-making than their sober peers. People who act more impulsively than sober individuals are also more likely to drop out of treatment for stimulants like cocaine.

One of the reasons people draw themselves to drugs in the first place is that they may have a mental illness that mimics the effects of these drugs, so they seek the drug to try and alleviate symptoms they are already experiencing naturally. Using drugs almost always makes the mental illness worse in the long run, even if the user finds short-term relief.

Mental illnesses cause altered levels of neurotransmitters and most notably affect serotonin levels and production. That’s why many withdrawal and intoxicating symptoms mimic different mood states that arise during episodes of mental and mood disorders.

Specific Drugs and their Effects on Serotonin


Studies show that after you take cocaine, your serotonin levels increase. A large dose of cocaine can look like a manic episode and lead to exquisite feelings, self-absorption, lack of desire to sleep, and profound paranoia.

When someone has been using coke for a long time, they go through withdrawals. Their withdrawals produce dysphoria and anhedonia (unable to derive pleasure from previously enjoyable activities). Depression and anxiety are also common. These behavioral and mental changes are a direct result of profound fluctuations of serotonin in the brain.


Serotonin dramatically increases when a user takes MDMA (ecstasy). Those on ecstasy experience a significantly heightened mood expressed through euphoria, happiness, and sometimes mania. Their sense of well-being increases, and most people high on MDMA experience a level of extroversion that is uncommon in their lives.


Meth users experience an unnatural heightening of serotonin levels. When meth users experience withdrawals, they often face dysphoria, fatigue coupled with insomnia, or conversely, hypersomnia.

Their appetites increase, and they experience an agitation of their psychomotor reflexes, which causes ticks and a need to move (such as pacing around a room). Their thoughts and movements may slow down after initial hyperactivity, and they often have very vivid nightmares.

How to Reverse Course & Get Help for Drug Addiction

Serotonin and its relation to substance abuse are important to understand as the effects of serotonin overstimulation and withdrawal are critical in sympathizing with what a drug user is experiencing and seeking when they get high. Most drugs release serotonin in some form, and almost all prolonged drug use affects the body’s ability to produce serotonin.

The rehabilitative community understands drug use and serotonin, and experts know how to handle the body’s tendency to have unbalanced neurotransmitters.

Medically supervised withdrawals sometimes provide medicines that alleviate the pain caused by the lack of balance in neurotransmission by administering medications that work with available synapses. The medicine tricks the receptors on neurons into thinking the person has used when they have not.

If you or a loved one is suffering from an addiction to substances, it’s important to reach out for help. You can begin your recovery journey today by calling (888) 906-0952 right now to speak to licensed and compassionate professionals who understand what you’re going through. Don’t delay; your journey can start today.

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