How Does Addiction Occur In The Brain

How Does Addiction Occur in the Brain?

Experts describe addiction as a relationship between the individual and a certain activity or object. For an addict, this thing becomes more important than the activities he/she once considered vital. As a result, this creates an internal struggle – with the person torn between acting on it – or resisting it.

Addiction Occur in the Brain

Sadly, addiction can end up changing the brain in many ways.

How Addiction Affects the Brain

A drug, alcohol, or any addictive substance largely affects the neurons or the brain cells that work like switches that control information flow. They send messages by releasing neurotransmitters to the synapse, or the gap between a neuron and another. In the presence of drugs, the way these neurons send, receive, and process signals can be distorted.

How Addiction Affects the Brain

For example, marijuana and heroin can attach to the neurons and activate them. That’s because these chemicals act like the body’s natural neurotransmitters. But since they don’t work like the latter, these drugs end up prodding the neurons to send ‘abnormal’ messages throughout the brain.

As for amphetamine and cocaine, they can bring about two things. First, these drugs can end up releasing a large number of natural transmitters. Second, they could interfere with transporters, which could get in the way of the normal recycling process of neurotransmitters.

Brain Parts Affected by Addiction

An addictive substance can affect the brain parts that govern vital body functions. As a result, it leads to the compulsive use – the grand hallmark of addiction.

1. Basal Ganglia

This part of the brain brings about the positive forms of motivation, as well as the formation of habits and routines. It’s also in charge of the pleasurable effects of eating, socializing, or sex. Because of these activities, the basal ganglia is touted as the brain’s reward circuit.

Addictive substances activate this circuit, which leads to the feeling of a ‘high’. The constant use, however, makes the basal ganglia easier to adapt. This makes the area more sensitive, so the user only derives pleasure from the drug – and nothing else.

2. Extended Amygdala

This area of the brain is responsible for anxiety, unease, irritability, and other stressful feelings. Unfortunately, it becomes sensitized as substance use increases. As such, it can lead to the withdrawal that comes after the drug high. In the end, this makes the person want to take the substance once again.

Because of these effects, the user takes the drug to get rid of this uncomfortable withdrawal, rather than just getting a euphoric high.

3. Prefrontal Cortex

This part of the brain governs the person’s ability to think and plan. It also allows the individual to make decisions, solve problems, and exert self-control. As this is the last area of the brain to mature, this part makes teens more susceptible to addiction.

Substances affect the balance of this circuit, as well as that of the basal ganglia and the extended amygdala. Since the user loses his impulse control, he/she ends up compulsively seeking and using the substance.

4. Brain Stem

Addictive substances such as opioids affect the brain stem, which governs life-critical functions such as breathing. This is the reason why overdose causes respiratory issues – and eventual death.

How Addiction Produces Pleasure

Despite breakthroughs in science, experts still aren’t sure how addictive substances produce euphoria or pleasure. The popular consensus is that these substances help produce a surge in endorphins, which are the body’s naturally-occurring ‘opioids’. In the end, the excessive production of neurotransmitters at the basal ganglia trumps the smaller endorphin bursts produced by other ‘pleasurable’ activities such as eating, socializing, etc.

Dopamine and Addiction

Back in the day, euphoria was believed to be caused by the dopamine brought about by addictive substances. Today, scientists believe this to prod addicts to repeat the activities they find pleasurable, i.e. taking drugs or drinking alcohol.


Dopamine is normally released by the brain following a pleasurable experience such as eating or socializing. It causes changes in neural connections so that the person repeats the activity all over again. As such, it’s instrumental in the formation of habits.

Just as addictive substances bring about the release of endorphins that cause euphoria, they help produce higher amounts of dopamine as well. This helps reinforce the relationship between substance intake and the pleasure it brings. In the end, this surge makes the brain crave addictive substances rather than ‘healthy’ pleasurable activities.

Even in the absence of these substances, the person can crave them once they find themselves exposed to certain cues. After all, the brain remembers these triggers well. For example, a long-clean addict can develop the urge to take drugs after seeing the house (cue) where his/her addiction was developed.

Why ‘Addicts’ Lean Towards Substances

Addicts seek substances more because of the way they change the brain circuitry. For one, substance users produce fewer neurotransmitters in the basal ganglia. They also have a fewer number of receptors that help process these signals.

Addicts Lean Towards Substances

Because of these changes, an addict is no longer attracted to healthy rewards. In the long run, he/she can feel depressed, lifeless, ‘flat’, and unmotivated. To escape these negative emotions, he/she keeps on taking these drugs – which eventually leads to a more vicious addiction cycle. An addict also develops tolerance, which makes him/her take more quantities of the addictive substance.

Addictive Substances and their Long-Term Effects on the Brain

Apart from making you an ‘addict’, substances can also bring about harmful effects to your brain – both physically and mentally. These vary according to the substance taken.

1. Marijuana

Increased use can lead to long-term changes in mood, time and sensory perception, and motor skills. In the short run, it can affect memory, leading to an impairment in thinking and problem-solving.

2. Opioids

Chronic use of drugs such as heroin affects the brain’s white matter. As a result, the addict can have a hard time making decisions, regulating emotions, and responding to stress.

3. Stimulants

Cocaine and meth put the central nervous system to overdrive. As such, it can make the user more energetic, focused, and alert. Since it promotes wakefulness, it can improve the person’s attention span as well. These feelings are short-lived though and end up in a ‘crash’ that makes the person want to take more. In the end, it could lead to paranoia, anxiety, hallucination, and confusion.


Although substances badly affect the brain, these effects can be reversed. With the help of interventions such as biofeedback therapy, cognitive behavioral therapy, and dialectical behavioral therapy, among many others, an addict may revert to his/her ‘normal’ life.

Latest posts by Raychel Ria Agramon, BSN, RN, MPM (see all)