Addiction and the brain

Addiction And The Brain

Addiction is a devastating disorder which makes the sufferers lose control over their addictive behavior. They become obsessed with the addictive substance or behavior and constantly crave it even when it is affecting their life negatively. However, it can also adversely affect their brain significantly.

Table Of Contents


Addiction Is A Brain Disease

Although it is commonly believed that addiction is a character flaw, bad judgment or poor choice, in reality it is a complex and enduring brain disorder. Although treatment can help someone overcome this disease effectively, they are always prone to the risk of relapse. According to researchers 1 trying to understand the biology of this condition, there are a lot more factors at play than simply a lack of willpower or the right intentions in an addict. Dr. George Koob, director of the National Institute on Alcohol Abuse and Alcoholism explains that it is not a moral problem. He adds “The brain actually changes with addiction, and it takes a good deal of work to get it back to its normal state. The more drugs or alcohol you’ve taken, the more disruptive it is to the brain.” It has been found that addictive substances and behaviors affect important brain regions that are crucial for our functioning and survival.

According to a 2017 study 2 , addiction can be legitimately explained as a ‘brain disease’. “Addiction is a brain disease of temptation and of choice itself. Addiction doesn’t replace choice, it distorts choice,” adds the study. The researchers believe that as dopamine mechanisms in the brain related to craving are sensitized, the ‘want’ experienced by addicts become more intense and amplified. These distorted cravings interact with the general function of choice but make it increasingly difficult. This is why it is difficult for addicts to stop as they experience sensitization of ‘wanting’. The main essence of addiction is “the addict’s own hyper-reactive brain response to drug cues or thinking about drugs,” adds the study. It is believed that this process is manifested psychologically as incentive salience or intense craving. This particular brain response of incentive-sensitization is one of the reasons why some people become addicted while others don’t.

Addiction Changes The Brain

Imaging studies 3 have also revealed that drug-addicted individuals experience “neurochemical and functional changes in the brains.” It has been observed that rapid and substantial dopamine increases can help to reinforce adverse effects of drug use. However, after repeated drug use and while withdrawal, a strong decrease is observed in brain dopamine function which are linked with dysfunction of prefrontal regions. “The changes in brain dopamine function are likely to result in decreased sensitivity to natural reinforcers since dopamine also mediates the reinforcing effects of natural reinforcers and on disruption of frontal cortical functions, such as inhibitory control and salience attribution,” add the researchers of the imaging study. It was revealed that substance craving or use can activate the frontal regions which involves a complex pattern of brain circuits, nucleus accumbens (reward), prefrontal cortex & cingulate gyrus (cognitive control), amygdala & hippocampus (memory), and orbitofrontal cortex (motivation).

However, not all experts agree with the brain disease model of addiction as some consider it to be an outcome of learning. According to a study 4 , the disease model proposes that the brain changes with addictive behavior. “Yet brains are supposed to change. They are designed to change,” adds the researcher. During our developing years, children and adolescents learn and experience a lot of new things which continues through their adult lives. This process of learning is associated with noticeable changes in our cortex & limbic regions. “Addiction is an outcome of learning, but learning that has been accelerated and/or entrenched through the recurrent pursuit of highly attractive goals,” explains the study.

The Addicted Brain

Studies 5 have found that addiction is primarily a “chronic, relapsing brain disease that leads to medical, mental, and social complications,” that can lead to sustaining changes in our brain. This chronic relapsing disorder involves three primary stages, namely –

  • Anticipation
  • Intoxication
  • Withdrawal

These stages are interconnected and get worse over time. According to a 2015 study 6 , “Critical neurotransmitters (i.e., gamma-aminobutyric acid, glutamate, dopamine, opioid peptides, serotonin, acetylcholine, endocannabinoids, corticotropin releasing factor) and neurocircuits (i.e., ventral tegmental area, nucleus accumbens, amygdala, cerebellum, prefrontal cortex) underlie the pathological changes at each of these stages.” The researchers found that at different stages, addiction involves various brain regions during the onset of the condition. It also involves complex actions related to our neurobiological systems. “Alcohol and drugs of abuse interact with many peptide and neurotransmitter systems in distinct regions of the brain,” adds the study. All addictive substances involve similar traits which regulate the reward system in our brain that are crucial for commencing and sustaining fundamental behaviors necessary for our survival, like eating and reproducing. A 2001 study 7 found that addictive substances can “exert influence over the brain reward pathway either by directly influencing the action of dopamine within the system, or by altering the activity of other neurotransmitters that exert a modulatory influence over this mesolimbic dopaminergic pathway.”

Different factors determine how our brain will respond to the substances, behaviors, frequency, intensity and stages of addiction. For instance, when a person consumes cocaine, a psychoactive drug, they typically experience euphoria as it affects the region of the brain which regulates motivation and pleasure. Due to the rapid release of the neurotransmitter dopamine, a brain chemical that manages mood and other functions in the brain & body, the addict feels an intense craving to seek and continue their behavior despite harmful effects. Once addicted, the person can experience adverse effects in their body and nervous system. Physical symptoms may include unusual sensations, nausea, hallucinations, paranoia, rapid heartbeat etc. It can also cause abnormal behavior as well. A 2011 study 8 states that “The crucial brain reward neurotransmitter activated by addictive drugs is dopamine.” It adds “virtually all addictive drugs are functional dopamine agonists – some direct, some indirect, some even transsynaptic.”

Addiction & Brain Chemistry

Being addicted to something affects the brain’s reward & pleasure circuits. Instead of making us question our decisions and analyze the consequences, it makes us crave for the addictive substance more. It can also affect the emotional circuits that sense danger causing intense stress and anxiety in the person when they are not consuming the substance or engaging in the behavior they are addicted to. Although people consume drugs and alcohol initially to feel pleasure, eventually they become trapped to their own addictions to prevent themselves from feeling the negative effects instead of feeling better. Repeated exposure to addictive substances or behavior can also impact the prefrontal cortex that is involved in decision making. Ironically, this is the brain region that can help us realize the problems associated with addictive behaviors and substances. Drugs or alcohol abuse can lead to reduced activity in our frontal cortex which makes it difficult for the addicted person to function normally when to stop consuming drugs or alcohol.

How Addiction Impacts Cognition?

Addiction affects certain regions of the brain and neural processes 9 which are associated with regulating crucial cognitive functions, such as memory, attention, reasoning, impulse control and learning. “From a psychological and neurological perspective, addiction is a disorder of altered cognition,” found a 2010 study 10 . When someone consumes illicit drugs frequently, these brain regions & processes develop intense maladaptive interconnections among environmental stimuli and drug abuse. This can influence cravings and behaviors associated with seeking drugs. Such cognitive deficits can make it challenging for the person to practice self-control and refrain from engaging in addictive substances or behaviors. “The developing brain is particularly susceptible to the effects of drugs of abuse; prenatal, childhood, and adolescent exposures produce long-lasting changes in cognition,” explains the study. The researchers found that individuals with psychiatric disorders are more likely to engage in substance abuse which can further worsen their cognition in addition to adverse cognitive issues from their mental illness.

“Drugs alter normal brain structure and function in these regions, producing cognitive shifts that promote continued drug use through maladaptive learning and hinder the acquisition of adaptive behaviors that support abstinence,” add the researchers.

Stabilizing The Addicted Brain

However, with effective treatment involving cognitive behavioral therapy (CBT), dialectical behavioral therapy (DBT), biofeedback therapy and Electroencephalograms (EEG), the brain of an addicted individual can be soothed and stabilized over time. Treatment and recovery primarily depends on the intensity of the addiction as well as the individual. For some, the process can be relatively easier while for some other individuals, it may require years of therapy, treatment & follow-up. Moreover, lifestyle changes and support of loved ones can also be significant factors in the recovery process.

References:
  1. Biology of addiction. (2017). NIH News in Health. https://newsinhealth.nih.gov/2015/10/biology-addiction []
  2. Berridge K. C. (2017). Is Addiction a Brain Disease?. Neuroethics, 10(1), 29–33. https://doi.org/10.1007/s12152-016-9286-3 []
  3. Volkow, N. D., Fowler, J. S., & Wang, G. J. (2003). The addicted human brain: insights from imaging studies. The Journal of clinical investigation, 111(10), 1444–1451. https://doi.org/10.1172/JCI18533 []
  4. Lewis M. (2017). Addiction and the Brain: Development, Not Disease. Neuroethics, 10(1), 7–18. https://doi.org/10.1007/s12152-016-9293-4 []
  5. Fluyau D, Charlton TE. Addiction. [Updated 2020 Nov 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549783/ []
  6. Herman, M. A., & Roberto, M. (2015). The addicted brain: understanding the neurophysiological mechanisms of addictive disorders. Frontiers in integrative neuroscience, 9, 18. https://doi.org/10.3389/fnint.2015.00018 []
  7. Tomkins, D. M., & Sellers, E. M. (2001). Addiction and the brain: the role of neurotransmitters in the cause and treatment of drug dependence. CMAJ : Canadian Medical Association journal = journal de l’Association medicale canadienne, 164(6), 817–821. []
  8. Gardner E. L. (2011). Addiction and brain reward and antireward pathways. Advances in psychosomatic medicine, 30, 22–60. https://doi.org/10.1159/000324065 []
  9. Institute of Medicine (US) Committee on Opportunities in Drug Abuse Research. Pathways of Addiction: Opportunities in Drug Abuse Research. Washington (DC): National Academies Press (US); 1996. 3, Neuroscience. Available from: https://www.ncbi.nlm.nih.gov/books/NBK232964/ []
  10. Gould T. J. (2010). Addiction and cognition. Addiction science & clinical practice, 5(2), 4–14. []
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