How Do Drugs Affect The Nervous System?

Drugs impact the entire nervous system in many ways. They do so mostly through affecting neurotransmitters such as dopamine and other naturally occurring chemicals in the brain.

Drugs have a profound impact on the reward center of the brain, often causing a rush of euphoria or a “high,” which over time can cause compulsive drug-seeking, drug-using behaviors.

How The Nervous System Works

The nervous system is made up of two main components: the central nervous system (CNS) and the peripheral nervous system (PNS).

The brain and spinal cord make up the CNS, and the PNS is made up of the somatic and autonomic nervous systems. Both the CNS and PNS are affected by substance abuse.

The brain controls all functions of the body and is made of cells called neurons. These cells have transmitters and receivers that enable them to communicate with each other.

When a neuron wants to communicate with another cell, it sends a neurotransmitter across the gap between the two cells, which is called the synapse. The cell receiving the message has a receptor that receives the neurotransmitter and changes itself according to whatever the message is.

Sometimes molecules called transports take the neurotransmitter back to the original neuron, which ends the communication between the two cells.

In the PNS, sensory nerves carry information to the brain, such as when you touch a hot surface and pull your hand away. The autonomic nervous system controls inner organs that aren’t controlled consciously, such as the heart.

Areas Of The Brain Affected By Drugs

The brain has several parts to it that each control certain aspects of your voluntary and involuntary bodily processes as well as emotions and memory.

The three sections most commonly affected by drugs are:

• the basal ganglia, which is often called the reward center
• the extended amygdala, from which feelings of anxiety, unease, and irritability come
• the prefrontal cortex, where thinking, making decisions, solving problems, planning, and exerting self-control occur

The prefrontal cortex is the last part of the brain to fully develop. This is one of the reasons why teen drug and alcohol use can have a lasting impact.

In general, drugs interact with these parts of the brain by mimicking neurotransmitters and sending abnormally intense messages throughout the brain.

Or drugs act on the neurons themselves, causing them to release a lot of neurotransmitters or prohibit the return of those transmitters.

Types Of Drugs And Their Effects On The Nervous System

There are two main categories of drugs that describe the effects that they have on the brain: stimulants and depressants.

A depressant drug is less about causing depression, as both stimulants and depressants can cause poor mental health, and more about lowering or depressing brain function.

Stimulants have the opposite effect. This has less to do with making you feel happy and more to do with speeding up or stimulating your nervous system.

The Effects Of Stimulant Drugs On The Nervous System

Stimulant drugs have the effect of speeding up your nervous system, which may cause a boost in energy.

Side effects of stimulants include:

• high heart rate
• high blood pressure
• irritability
• violence
• depression (after use)
• heart attack

Methamphetamine

Methamphetamine has an intense effect on the CNS for a couple of reasons. The drug does not fully metabolize after you ingest it. As a result, it remains active in the brain, giving its effects a longer duration.

The other reason it has an intense stimulant effect is because of how it interacts with dopamine neurotransmitters. Meth blocks the reuptake of dopamine and it also increases the release of dopamine.

The result is that high levels of dopamine remain in the synapses. This can have a toxic effect on nerve terminals.

In addition to the side effects listed above, meth can also create an intense itching that feels like bugs crawling on and under your skin. Scratching creates sores that can get infected and have a hard time healing.

Amphetamines

Amphetamines are chemically similar to methamphetamines but cause less intense effects.

Nevertheless, prescription amphetamines are addictive because of how they increase dopamine and norepinephrine in the brain.

When used as advised by a doctor, they can help increase cognitive function in people being treated for attention-deficit/hyperactivity disorder (ADHD).

However, amphetamines are controlled substances for their addictive properties.

Cocaine

Cocaine is a naturally occurring stimulant drug that is derived from the coca plant native to South America.

Cocaine is not as intense as methamphetamine, but it is still highly addictive because it produces intense feelings of pleasure.

The body quickly absorbs cocaine, which leads people to take large quantities to maintain the high.

Like meth, cocaine prolongs dopamine’s effects by preventing the reuptake of it, but it does not increase dopamine release the way meth does.

MDMA

MDMA is short for 3,4-methylenedioxymethamphetamine and is a stimulant drug with psychoactive properties. MDMA is generally thought of as a “party drug” and goes by the names molly and ecstasy.

MDMA targets three neurotransmitters in the brain:

• serotonin
• dopamine
• norepinephrine

MDMA causes the release of more serotonin, which is why feelings of intense happiness are associated with the drug.

However, this results in low amounts of serotonin after the drug is metabolized. People who take MDMA often feel depressed after using it.

They may also experience other problems resulting from low serotonin:

• memory loss
• confusion
• paranoia
• anxiety
• depression

The Effects Of Depressant Drugs On The Nervous System

Depressants are drugs that lower or depress activity in the CNS. They may interact with the same or similar chemicals as stimulant drugs, but the high ultimately has a different impact.

Side effects of depressants include:

• drowsiness
• confusion
• poor coordination
• slowed breathing
• difficulty concentrating

Cannabis

Marijuana is a depressant that has psychoactive properties through the main chemical in the plant that is responsible for the high, tetrahydrocannabinol (THC).

THC has a similar structure to a neurotransmitter in the brain called anandamide, which causes the body to recognize THC as normal.

This allows THC to affect the same areas of the brain that anandamide affects, resulting in disruptive changes to cognitive and physical abilities.

Abusing marijuana can result in difficulty with:

• thinking
• remembering
• balancing
• movements requiring coordination
• posture
• reactions

Benzodiazepines

Benzodiazepines are prescription medications or sedatives often prescribed by doctors to help people control anxiety.

Benzodiazepines include Xanax, Valium, clonazepam, and other such medications. “Benzos” work by increasing receptors for the neurotransmitter gamma-aminobutyric acid (GABA).

GABA is the brain’s natural way of dealing with anxiety and producing calm. Benzos also make you sleepy, which is why some are used as sleep medications.

Heroin And Opioids

Heroin, a natural opioid, and prescription opioids have similar effects on the brain. Both attach to specific mu-opioid receptors in the brain. These receptors help regulate pain messages from nerve cells to the brain.

Different opiates and opioids will have slightly different effects depending on the strength of the opioid that you take.

Prescription opioids include:

• OxyContin
• Vicodin
• Norco
• Percocet
• fentanyl

The National Institute on Drug Abuse (NIDA) reports that people do not normally have an opioid and heroin drug addiction. It is usually one or the other, although some people who use opioids will transition to heroin.

Opioids are known for inciting strong cravings and intense withdrawal symptoms that keep people from seeking treatment.

However, recovery from opioid use disorder (OUD) is possible, and medication-assisted treatment (MAT) can help with both cravings and withdrawal symptoms.

How Hallucinogens Affect The Brain

There are many types of hallucinogenic or psychedelic drugs, but all of them affect people by changing their perceptions of reality or making them feel detached or removed from the real world.

Research into exactly how psychedelic drugs such as LSD work is ongoing. In general, psychedelics interact with receptors in the brain called 5-HT2A, which normally interact with serotonin.

According to research, hallucinogens also block or disrupt communication between different parts of the brain, but much of the activity that psychedelic drugs stimulate comes from the prefrontal cortex.

Psychedelic drugs can cause brain damage that results in schizophrenia and permanent psychosis.

How Alcohol Affects The Brain

Alcohol has broad effects on the central nervous system, impacting several parts of the brain.

Areas of the brain affected by alcohol include:

• cerebral cortex
• frontal lobes
• hippocampus
• hypothalamus
• cerebellum
• medulla

This means that alcohol affects everything from motor skills to judgment.

Alcohol affects:

• speech
• thought processes
• self-control
• decision making
• memory
• coordination
• awareness
• body temperature
• heart rate
• ability to stay conscious

Addiction Treatment For Drugs And Alcohol

Drugs and alcohol have wide-ranging effects on the CNS, some of which have lasting consequences. But addiction treatment is always available, no matter how severe your substance use disorder may be.

Many addiction treatment centers offer both behavioral therapy and MAT, especially for opioid and alcohol use disorders, at the inpatient or outpatient level.

Some treatment centers will also provide medical detox for severe withdrawal symptoms.

Find Substance Abuse Treatment Today

Are you or a loved one facing substance abuse? You can find treatment today. Call us to learn more about your treatment options and how to access them.

Written by the Addiction Resource Editorial Staff