How Do Drugs Affect the Nervous System?

Drug abuse greatly affects one of the most vital systems in your body: the nervous system.

In the short term, drug abuse can cause the nervous system to speed up or slow down the transmission of vital messages between your brain and the rest of your body.

Long-term drug abuse can impede proper functioning of the nervous system. It can impact neuron transmission, cause nerve and tissue damage, contribute to brain damage, and reduce the functioning of vital organs.

What Is the Nervous System?

The nervous system is comprised of two main systems that run throughout your body: the central nervous system (CNS), which is made up of your brain and spinal cord, and the peripheral nervous system (PNS), which includes all of the nerves that extend from the spinal cord to the rest of your body.

Together, the CNS and PNS transmit messages throughout your body that instruct you to do essential functions, such as breath, move, see, smell, and think. The nervous system performs these additional functions:

Controlling heart rate
Releasing hormones
Regulating digestion
Protecting neurons and neurotransmitters
Influencing behavior and emotions

Drugs That Affect the Nervous System

Both recreational drugs and those prescribed for medical reasons impact the nervous system. The CNS, in particular, is impacted by drug use.

These drugs are well-known to impact the CNS:

Alcohol
Cocaine
Heroin
Amphetamines
Cannabis
Nicotine
Immunosuppressants
Antiepileptics
Nitrous oxide
Sedatives
Prescription pills

CNS stimulants, such as cocaine, speed up the transmission of messages sent throughout the body. CNS depressants, such as alcohol, slow them down. Hallucinogenic drugs distort the messages sent between neurons, leading to the psychedelic high that many people experience while on hallucinogens.

The pleasure centers of the brain, which receive neurotransmitters like dopamine, are affected by drugs of abuse, no matter which type of drug they are. As drugs enter the nervous system, they affect which messages are being sent as well as their transmission rate. People become addicted to drugs because intense messages of pleasure are rapidly released by the nervous system into the brain.

Short-Term Effects of Drug Abuse on the Nervous System

The effects of drugs on the nervous system vary from person to person and depending on which drugs are being abused. In general, you can expect to experience physical and psychological effects that will subside once the drug wears off, but these effects can also lead to dependency with extended use.

Short-term effects of recreational drugs on the nervous system vary according to the type of drug.

Cannabis
relaxation, altered perception, increased heart rate, low blood pressure, anxiety, paranoia, and difficulty concentrating
Cocaine
increased energy, increased alertness, feelings of happiness, lowered inhibition, increased confidence, and overstimulation of the heart and nervous system, which increases the risk of seizure, stroke, or heart attack
Ecstasy
increased alertness, talkativeness, amplified intensity of sounds and colors, anxiety, confusion, paranoia, increased body temperature, and dehydration
Speed
increased confidence and energy, increased alertness, reduction in appetite, agitation and aggression, confusion, paranoia, high blood pressure, and heart attack
Crystal meth
feelings of pleasure, increased confidence, amplified alertness and energy, sense of itchiness, dilated pupils, dry mouth, excessive sweating, increased heart rate and breathing, reduction in appetite, and increased sex drive

All of the above short-term side effects of drug use vary in intensity depending on your personal response to drugs, which drugs are being used, and how much of each drug is being taken. Once the effects of the high wear off, the side effects will likely too. It is possible, however, to experience more serious side effects, such as overdose, with any level of drug abuse.

Risk of Overdose

All drugs pose a risk of overdose when abused for recreational purposes. Drugs that directly impact the nervous system are particularly dangerous, as involuntary actions like breathing and heart rate can be affected. Additionally, your risk of overdose increases greatly with polydrug use, or using multiple drugs at once.

With CNS depressant drugs, overdose is common. They are known to impair cognitive function, as well as suppress vital functions, such as breathing and heart rate, to the point of death. CNS depressants slow brain activity. CNS depressants, such as opioid painkillers, serve important medical purposes when taken in low doses.

If doses are too high or if these drugs are combined with other depressants drugs, such as alcohol, the risk of a potentially fatal overdose is great. These CNS depressants are often abused for recreational purposes and frequently seen in overdoses:

Opioid painkillers
Sedatives
Alcohol
Hypnotics
Tranquilizers

When any of the above substances are taken in combination with each other, the depressant effects on the nervous system are compounded. If the nervous system is overwhelmed by messages to slow breathing and heart rate, you may stop breathing and your heart may stop beating altogether.

Long-Term Damage to the Nervous System

Studies have found that most people who are treated for a drug overdose are likely to be discharged from the hospital within one to two days. While the acute symptoms of an overdose can be treated, there are lasting effects of an overdose that can linger.

A recent study found that patients who were treated for an overdose due to CNS depressant drugs were significantly impaired in the following domains compared to the control group who had not experienced an overdose:

Prolonged reaction times
Poorer working memory and planning
More impulsive decision-making
Poor performance on tasks with increasing complexity

Research has found three main ways that certain drugs, such as methamphetamine, can cause physiological and biochemical damage to the brain and nervous system. Long-term damage includes the following issues:

Acute changes to neurotransmitters
Rewiring of the brain’s reward system
Death to brain cells

Long-term exposure to drugs that alter neurotransmitters and brain cells can cause irreversible damage. However, most of the brain dysfunction is likely to be reversed with abstinence over time. Damage to the nervous system is not likely to heal quickly, taking up to 18 months of sober living for many people to make a full recovery.

Co-Occurring Conditions

Prolonged drug use can cause long-term damage to the nervous system that manifests in the form of co-occurring conditions. These are additional symptoms of prolonged drug abuse on the nervous system that are not necessarily associated with an overdose:

Memory loss
Depression
Anxiety
Vein and tissue damage
Infectious diseases (associated with injection drug use)
Weakened immune system
Changes in the brain’s reward system

The above physical and mental health conditions are likely to occur with extended use of any substances that interfere with the normal functioning of your nervous system. The occurrence of these conditions is often progressive and gets worse with continued and more severe drug use.

Many of these conditions can be treated, especially once drug use is stopped. Mental health issues, such as depression and anxiety, are very common in people with extended drug use.

Abstinence coupled with appropriate counseling can alleviate most mental health symptoms. Appropriate medical care can improve weakened immune systems and treat or monitor medical complications that arose as a result of drug use.

Reversing Damage to the Nervous System

With time, damage to the nervous system is expected to reverse itself in most people. The extent and duration of drug abuse, and how the individual’s body responded to drug abuse, impact this recovery period. Fortunately, CNS repair is possible.

Whether treating CNS injury due to substance abuse or neurological disease, it is possible to repair damage caused to the CNS. These strategies have been developed to repair damage to the nervous system:

Cell replacement
Reconstruction of damaged neural tissue
Rewiring of the CNS
Medicines

The above strategies focus on promoting neural cell growth so healthy neural connections can be reestablished and neural networks can function properly once again. Due to neuroplasticity, or the brain’s ability to form new connections in response to the experiences it encounters, there is a high potential for neural recovery.

Neuroplasticity is the brain’s way to compensate for injury or disease. New pathways are formed as healthy, undamaged nerve endings grow and connect with other healthy nerve cells.

Signs That You Need Treatment to Address the Damage

If you have a history of drug abuse that has made notable impacts on your nervous system, you will benefit from treatment to address the damage. Drug abuse is difficult to overcome on your own, but it is possible with the support of a proper recovery program.

These are signs that you could benefit from treatment:

Health problems caused by drug abuse
Persistent mental health issues
Taking an increasing amount of the drug over time to achieve the desired effects
Inability to function normally without the drug in your system
Cravings and uncontrollable urges to use the drug
Inability to stop using the drug even when you want to

The National Institute on Drug Abuse (NIDA) explains that addiction is a treatable disease. Decades of research on addiction and recovery have contributed to the development of evidenced-based treatment programs that help people quit using harmful substances and recover from the damage their drug abuse caused to their bodies and minds.