Substance abuse changes the brain in the short-term to create euphoria and other reactions associated with the “high” that is part of the drive to use drugs or alcohol.
However, long-term drug use can also result in more fundamental changes in the brain that can last for years or even a lifetime.
While not all drugs have permanent effects on brain chemistry and structure in the long-term – or even the short-term – most drugs, if abused consistently for many years, can cause fundamental changes in brain structure that affect the individual throughout life. These fundamental changes include addiction or other substance use disorders, which are chronic mental health disorders that can affect a person throughout life even after going through rehab. As a result, they require continued management and care.
Drugs and the Brain
As explained by the Genetic Science Learning Center, long-term drug use results in changes in the brain’s chemistry and structure, primarily affecting the circuitry around pleasure and reward, memory and learning, and motivation. These changes are basic factors in the development of substance use disorders and addiction, as the individual begins to develop a compulsion to use the substance that is harder and harder to control. The changes include:
- Increased production of dopamine and changes in production of other neurotransmitters
- Loss of neurotransmitter bonding sites and decrease in brain cell activity
- Rewiring of certain brain cell and neurochemical systems to adapt to the drug use
- Cell death, or permanent loss or change of brain function
As a result of the physical damage to these chemical systems and their receptors, long-term drug abuse can result in other changes that can lead to brain damage and permanent alterations in brain structure. These problems are particularly prevalent in young people whose brains are still developing while they are using these drugs.
Opiates and Benzodiazepines
Nervous system depressants include opioid drugs, benzodiazepines, and alcohol, among others. Extended opioid use can result in a decrease in dopamine receptors in the brain, which in turn can lead to diminished feelings of pleasure; this can result in tolerance, which is the need to use more of the drug to get the same response. The result is often for the person to increase use of the drug to try to get the same high that was experienced before tolerance was reached. For many people, the loss of these dopamine receptors can be permanent, which leads to continued cravings for the drug even long after conventional rehab treatment is over.
- Opioid overdose can also cause permanent brain damage. One example is described in a news article from CBC Canada in Calgary, where a young man experienced permanent brain damage as a result of taking a pill that likely contained fentanyl, overdosing on the drug. This type of brain damage results from the slowed respiration and lack of oxygen to the brain that can occur with an opioid or depressant overdose. Overdose becomes more likely the longer a person is using opioid drugs due to tolerance and subsequent increases in dosage.
- Similarly, long-term benzodiazepine use – such as diazepam and alprazolam, or Valium and Xanax – can lead to damage to memory and brain atrophy, as evidenced by an article from Psychology Today. This corresponds with enlarged cerebral ventricles, as measured through radiology, and it is a particular risk for older people, who have often been overprescribed these drugs for mental health disorders like depression and anxiety.
Alcohol and Wernicke-Korsakoff Syndrome
Also in the depressant category is alcohol, which presents a specific brain damage risk compared to other depressants. Alcohol can cause a deficiency in vitamin B12, also known as thiamine, which can have dire consequences for the brain. According to the National Institute on Alcohol Abuse and Alcoholism, thiamine deficiency can result in Wernicke-Korsakoff syndrome, which is a combination of Wernicke’s encephalopathy and Korsakoff’s psychosis. The symptoms that result from these disorders include:
- Problems with eye and other body muscles
- Memory and learning problems
- Lack of muscular coordination
These symptoms are the result of damage to specific areas of the brain related to the thiamine deficiency. While not all of them may be present, Wernicke-Korsakoff syndrome may still be a factor.
Stimulants include drugs like amphetamines, methamphetamine, and prescription attention deficit hyperactivity disorder (ADHD) drugs, including Adderall. These drugs can have a similar effect to depressants on the dopamine system, causing dopamine receptors to become inactive. In addition, stimulants can cause problems with the serotonin system, as described in a study from Neuropharmacology. This depletion of neurochemical receptors can result in a condition called anhedonia, which is a lack of the ability to feel pleasure at all. This is particularly apparent with methamphetamine use, but it can occur with other stimulants as well.
Another study, described in an article from Medical Daily, notes that ADHD prescription stimulant abuse can also result in diminishment of intellectual capability and performance, especially when used by those who have not been prescribed the drugs. This occurs when the drugs are used as “smart drugs” by students who want to improve their academic performance. Particularly in young people whose brains have not finished developing, this can be a major issue as it can impair development as well.
Many people who use marijuana – especially for medical purposes – are quick to say that it is one of the least harmful drugs out there. However, research continues to throw that idea into question. For example, a recent study from Psychological Medicine demonstrates that smoking marijuana that is high in tetrahydrocannabinol (THC), the psychoactive substance in marijuana, can cause damage to a part of the brain called the corpus callosum, which connects the left and right brain hemispheres and helps with neural coordination and communication across both sides of the brain. This, in turn, can contribute to the development of psychosis in individuals who are prone to the condition; however, damage to the corpus callosum is found in individuals who use high-potency marijuana regardless of the occurrence of psychosis.
In addition, studies demonstrate that marijuana use while pregnant may contribute to changes in brain development in the fetus. This can lead to learning and memory challenges in the children of women who used marijuana while pregnant.
More research needs to be done on the effects of other drugs on the brain, such as hallucinogens and some club drugs. For example, hallucinogens have limited evidence of damage that can result in persistent psychosis, a lasting psychosis that has been seen in some people after long-term hallucinogen use, and hallucinogen persisting perception disorder, which consists of visual disturbances and other symptoms that can persist after heavy hallucinogen use, as described by the National Institute on Drug Abuse.
While other drugs require more research to understand the long-term effects of abuse on the brain and other parts of the body, there is one aspect of abusing addictive substances that can change the brain regardless of drug type, and that is addiction. This condition is the result of changes in the brain caused by long-term drug abuse – or sometimes even short-term abuse – that cause the person to develop a compulsive need to use the substance. Addiction is itself a fundamental change in brain structure and function, and demonstrates the challenges that substance abuse can present to physical and mental health.
Addiction and the Brain
Addiction is basically defined as the inability to control substance use; it is considered to be a chronic brain disorder that affects the systems controlling pleasure and reward, memory, and motivation, making it difficult to stop drug use even in the face of severe consequences of use. This definition of addiction is presented by the American Society of Addiction Medicine, and it was developed through ASAM’s study and understanding of individuals who struggle with substance abuse.
Thankfully, while these brain changes are often permanent and unable to be changed, addiction treatment can help people learn to manage addiction and overcome the cravings and other challenges that are associated with drug abuse. While many of the brain issues that are caused by addiction and substance abuse cannot be reversed completely, learning how to manage the symptoms of addiction can help the individual achieve recovery and return to the most fruitful life possible, without continued substance abuse.