How Does Substance Use Impact Your Brain?

Drugs and alcohol affect the brain and central nervous system by altering how neurons send, receive, and process signals. These changes impair memory, decision-making, mood regulation, and physical coordination. Over time, substance misuse rewires the brain’s reward pathways, contributing to dependence, withdrawal symptoms, and long-term neurological damage. 

In Nevada, an estimated 9.5% of adults experienced a substance use disorder in 2023, a rate above the national average. Understanding how different substances interact with brain systems is critical to recognizing early warning signs of addiction and seeking professional treatment, especially in communities like Las Vegas, where access to trauma-informed, holistic care is life-saving.

What Happens in the Brain When You Use Drugs or Alcohol?

When you use drugs or alcohol, they disrupt everyday brain communication by interfering with neurotransmitters like dopamine, serotonin, GABA, and glutamate. Over time, these disruptions rewire the brain’s reward system, making substance use feel essential for emotional or physical survival.

The following effects happen in the brain when you use drugs or alcohol:

• Distort how you perceive pleasure and pain: Substances like opioids flood the brain with dopamine, creating intense pleasure while also blunting pain signals. This reinforces compulsive use and tolerance over time.
• Reduce impulse control: Chronic drug use impairs the prefrontal cortex, the brain region responsible for decision-making and self-control. A study by Volkow et al., 2004 showed reduced gray matter volume in this area among people with substance use disorders.
• Impair cognitive functions such as memory, attention, and learning: Long-term alcohol and stimulant use have been linked to deficits in verbal memory and executive functioning, even after abstinence, as studied by Fernández-Serrano et al., 2010, titled “Drug and Alcohol Dependence.”
• Increase the risk of mood disorders and psychiatric symptoms: Substance-induced changes in serotonin and dopamine systems contribute to depression, anxiety, and psychosis, especially with chronic use of stimulants, cannabis, or hallucinogens.

Which Brain Disorders Are Caused by Alcohol and Drug Use?

Alcohol and drug use cause severe brain disorders that impair memory, cognition, emotional regulation, and behavior. Some conditions are temporary, while others become permanent, especially with chronic use or early exposure during adolescence. 

The following are the brain disorders caused by alcohol and drug use:

Wernicke-Korsakoff Syndrome (WKS) – Linked to Alcohol

Wernicke-Korsakoff Syndrome (WKS) is a severe neurological disorder associated with long-term alcohol abuse, caused primarily by a deficiency in thiamine (vitamin B1). As studied by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), Alcohol interferes with the absorption and storage of thiamine, which the brain needs for energy metabolism. WKS has two stages: Wernicke’s encephalopathy (acute confusion, loss of muscle coordination, and abnormal eye movements) and Korsakoff’s syndrome (chronic memory problems and confabulation). 

Alcohol-Related Dementia

Chronic heavy alcohol use leads to alcohol-related dementia, a condition marked by progressive cognitive decline not attributable to other neurodegenerative diseases. Affected individuals show impairments in memory, learning, judgment, and emotional regulation. Neuroimaging studies by Harper C. et al. 2009, titled “Alcohol and Alcoholism,” reveal brain atrophy, particularly in the frontal lobes and hippocampus, which are necessary for memory and executive functioning. Unlike Alzheimer’s, alcohol-related dementia partially improves with abstinence, but the damage becomes irreversible if drinking continues.

Cocaine-Induced Psychosis and Cognitive Dysfunction

Cocaine use is strongly linked to acute psychiatric symptoms and long-term cognitive dysfunction. Short-term use triggers hallucinations, paranoia, and aggressive behavior, while chronic use alters brain chemistry, particularly in the dopamine system. This leads to impairments in attention, working memory, and decision-making, as studied by NIDA. Neuroimaging reveals decreased activity in the prefrontal cortex, which governs impulse control and judgment. These effects may persist even after periods of abstinence.

Opioid-Related Cognitive Impairment

Prolonged use of opioids like heroin, fentanyl, or prescription painkillers results in persistent cognitive impairments, particularly in executive function, attention, and emotional regulation. Studies by NIDA show that opioid use alters brain regions such as the anterior cingulate cortex and prefrontal cortex, areas essential for self-control and motivation. Over time, this reduces a person’s ability to make rational decisions or control compulsive behaviors, which reinforces the addiction cycle.

Methamphetamine Neurotoxicity

Methamphetamine is one of the most neurotoxic substances commonly abused. It causes severe damage to dopamine and serotonin neurons, which leads to long-term issues with memory, learning, motor coordination, and emotional stability. Brain scans show significant loss of gray matter and reduced activity in the limbic and frontal regions of the brain. These structural changes last for years and are sometimes irreversible, particularly with prolonged, high-dose use.

Cannabis-Induced Neurocognitive Decline

While often perceived as harmless, chronic marijuana use, especially when initiated during adolescence, has been linked to lasting neurocognitive decline. Research by SAMHSA shows that frequent cannabis users experience lower IQ scores, impaired working memory, and poor decision-making skills. These effects are more pronounced in individuals who began using before age 18, as the developing brain is more vulnerable to cannabinoid exposure.

Hallucinogen Persisting Perception Disorder (HPPD)

HPPD is a rare but disabling condition triggered by the use of hallucinogens such as LSD or psilocybin. Individuals with HPPD experience ongoing visual disturbances, such as halos, trails, and geometric hallucinations, long after drug use has stopped. This disorder also involves derealization and anxiety. While not fully understood, researchers believe HPPD stems from alterations in the brain’s visual processing pathways.

How Does Substance Use Lead to Cognitive and Behavioral Impairments?

Substance use leads to both short-term and lasting impairments in cognition, behavior, and emotional regulation by altering neurotransmitter systems and disrupting brain regions responsible for decision-making, memory, and mood. These impairments impact daily functioning, relationships, and the ability to recover without professional support.

Substance use leads to the following cognitive and behavioral impairments:

• Poor memory and attention: Difficulty concentrating, retaining information, or completing tasks.
• Disinhibition and impulsivity: Engaging in risky behaviors or acting without considering consequences.
• Distorted perception or delusional thinking: Hallucinations, paranoia, or an altered sense of reality.
• Mood instability and aggression: Sudden emotional swings, irritability, or violent behavior.
• Reduced executive function: Impaired judgment, planning, and self-regulation.

Substance use is linked to the following cognitive decline:

• Alcohol: Causes Wernicke-Korsakoff syndrome (thiamine deficiency), alcohol-related dementia, and pellagra (niacin deficiency)
• Benzodiazepines: Long-term use impairs memory, problem-solving, and attention
• Cocaine: Impairs working and verbal memory, causes paranoia
• Methamphetamine: Alters brain structure, linked to memory and decision-making deficits
• Cannabis: Affects attention span, learning, and brain development in teens
• Opioids: Reduce planning and impulse control, and cause persistent executive dysfunction
• Hallucinogens and PCP: Lead to cognitive distortions, panic attacks, or long-term psychosis
• Inhalants: It results in permanent neurological damage

Can Drugs and Alcohol Cause Seizures?

Yes, drugs and alcohol can cause seizures, especially during withdrawal or overdose. Substances most frequently associated with seizure activity include:

• Alcohol: Withdrawal seizures are common, especially in chronic drinkers
• Benzodiazepines: Seizures occur during withdrawal
• Cocaine and Methamphetamine: Toxic levels lead to seizures and cardiovascular strain
• MDMA: Causes seizures related to electrolyte imbalances or overheating
• Inhalants: High toxicity levels from glue, paint, or aerosol sprays induce seizures

How Do Drugs and Alcohol Increase the Risk of Stroke?

Substance use increases stroke risk by affecting blood pressure, heart rate, and blood vessel function. Two main types of stroke, ischemic (blocked blood flow) and hemorrhagic (bleeding in the brain), both of which are triggered by drugs or alcohol. In Las Vegas, where stimulant use is on the rise, stroke risk due to substance misuse is an increasing concern.

The following substances are associated with stroke:

• Heavy use of alcohol raises blood pressure and contributes to vascular inflammation
• Cocaine causes arterial spasms and inflammation that raise stroke risk
• Amphetamines and MDMA increase heart rate and blood pressure, sometimes leading to hemorrhagic stroke
• Heroin causes both ischemic and hemorrhagic strokes, especially when injected
• Hallucinogens trigger severe hypertension and vasoconstriction, leading to ischemia

What Are the Neuromuscular Effects of Substance Use?

Neuromuscular effects of substance use include weakness, numbness, burning sensations, or paralysis. Substance use disorders caused by drugs and alcohol affect nerves, muscles, and the spinal cord. 

Chronic alcohol use causes alcoholic neuropathy (nerve damage) and alcoholic myopathy (muscle weakness and pain). Heroin is linked to Guillain-Barré syndrome and rhabdomyolysis, a condition involving muscle breakdown that leads to kidney damage. Inhalants, especially solvents like glue, result in severe neuropathy or spinal cord injury. Some of these effects improve with abstinence and medical treatment, while others require long-term rehabilitation.

How Can Drugs and Alcohol Lead to Movement Disorders?

Drugs and alcohol lead to movement disorders by disrupting the brain regions responsible for motor control. Substance-induced movement disorders are hyperkinetic, involving involuntary movements such as tremors, spasms, or repetitive motions, or hypokinetic, involving slowed movements, stiffness, or reduced motor activity. 

These effects occur during acute intoxication, withdrawal, or as a result of long-term neurological changes caused by chronic use. Common substances linked to these disorders include cocaine, methamphetamine, opioids, and inhalants.

Does Drug or Alcohol Use Increase the Risk of Traumatic Brain Injury?

Yes, drug or alcohol use increases the risk of traumatic brain injury (TBI) due to impaired judgment, impulsivity, and motor coordination. In Nevada, where nightlife and high-risk behaviors are common, this risk is especially pronounced. 

Common causes of TBI in people using substances include:

• Car accidents
• Physical altercations
• Falls
• Burns or other risky behaviors

How Can The Brain Heal After Drug or Alcohol Use?

The brain can heal after substance misuse, but recovery depends on the substance involved, duration of use, co-occurring conditions, and the presence of supportive therapies. 

Brain healing after drug or alcohol use involves:

Detox and medical stabilization: The first step in recovery, detox removes substances from the body under medical supervision while managing withdrawal symptoms safely.

Cognitive rehabilitation therapy: Psychotherapies help restore attention, memory, and executive function affected by substance use through structured cognitive exercises and treatment.

Nutritional support and brain-healthy lifestyle changes: A balanced diet, hydration, and regular sleep support brain repair and improve mood and energy levels.

Trauma therapy and emotional regulation techniques: Addressing underlying trauma with evidence-based therapies like EMDR or DBT helps improve emotional control and reduce relapse risk.

Holistic services: These complementary approaches reduce stress, promote neuroplasticity, and support overall brain and body healing.

Where Can You Find Brain-Focused Addiction Treatment in Nevada?

If you or someone you love is struggling with the brain-related effects of substance use, The Nestled Recovery Center in Las Vegas offers a safe, compassionate environment where healing begins. Our dual diagnosis care team includes licensed professionals trained in trauma therapy, neuroscience-informed recovery, and holistic modalities designed to restore brain health.