Dopamine and addiction
Dopamine is a key neurotransmitter in the brain that plays a crucial role in the reward system, influencing behaviors related to pleasure and reinforcement. It is involved in various functions, including movement, mood regulation, and cognition. Dopamine's relationship with addiction is complex; addictive substances often increase dopamine levels, leading to heightened feelings of euphoria that reinforce drug-seeking behavior. When drugs mimic dopamine's effects, they can cause significant surges of the neurotransmitter in areas like the nucleus accumbens, enhancing the rewarding experience. Over time, chronic drug use can deplete dopamine receptors, resulting in diminished pleasure from both drugs and natural rewards, thereby creating a vicious cycle of addiction. This cycle often leads to increased substance use as individuals seek to restore the previously experienced dopamine highs. Recent research has also identified a potential link between social media use and dopamine production, raising concerns about its addictive qualities and effects on mental health, particularly among adolescents. Understanding dopamine's role in addiction highlights the need for comprehensive approaches to prevention and treatment, as well as the implications of modern technological influences on behavior.
On this Page
Subject Terms
Dopamine and addiction
DEFINITION: Dopamine, a catecholamine neurotransmitter, is the brain’s reward and anticipation (craving) molecule. It plays an important role in the reinforcing effect of drugs and in the powerful cycle of brain dysfunction they cause.
ALSO KNOWN AS: Dihydroxyphenylethylamine
The Dopamine System
In the central nervous system, dopaminergic (dopamine-producing) neurons reside only in a few areas, such as the substantia nigra of the midbrain, but establish connections with numerous brain regions. Dopamine (DA) dysfunctions in Parkinson’s disease and schizophrenia, for example, suggest that projections from midbrain to certain brain regions (such as the striatum and frontal cortex) are involved in behavioral reactions controlled by rewards. Extensive studies conducted since the mid-twentieth century revealed that DA is involved in the generation of movement, cognition, attention, mood, reward, reward expectation, addiction, and stress. DA also serves various other functions, including as a hormone helping to stop breast milk flow, as an antipsychotic agent, in the function of the kidneys, and in regulating nausea.
Pleasant behavioral events (natural reinforcers such as eating, drinking, exercising, and sexual activity) stimulate the brain’s reward (limbic) circuitry, causing DA release from dopaminergic neuron terminals. The information is relayed to the frontal lobe of the brain and stored in memory. The stored memory leads to behaviors directed at procuring the reward.
Dopamine in Addiction
Dopamine involvement in multiple stages of addiction is a complex phenomenon and the subject of intense research efforts. The need for DA and its pleasurable effect can be satisfied by substances that mimic the action of this molecule on its receptor.
These substances (addictive drugs) induce transitory, exaggerated increases in DA outside the cells in a deep brain area called nucleus accumbens, a key component of the reward system. This occurs through enhanced release or decreased recycling of the neurotransmitter. The DA surges mimic or exceed the physiological responses that follow natural rewards. A 2015 article published in the journal Nature Reviews Neuroscience suggested that alcohol and stimulants including nicotine, cocaine, and methamphetamine particularly rely on changes in dopamine levels to cause addiction. For other addictive drugs, including heroin, dopamine is thought to be more of a supporting factor in the development of addiction.
Human brain imaging studies demonstrate that the subjective feeling of euphoria occurring during intoxication associated with DA increases in deep brain nuclei. The drug-induced surge of the neurotransmitter is especially rewarding for persons with abnormally low densities of certain DA receptors (such as D2DR). Low receptor availability is associated with an increased risk for abuse of cocaine, heroin, methamphetamine, alcohol, and methylphenidate.
The euphoria triggers a reinforcing pattern that “instructs” the person to repeat the rewarding behavior of abusing drugs. As the abuse continues, long-lasting and significant adaptive decreases in DA brain function occur. These decreased levels reduce the effect of the neurotransmitter on the reward system and force the addicted person to keep abusing drugs in an attempt to normalize DA function.
When larger amounts of the drug are required to achieve the same DA high, desensitization (tolerance) occurs. Chronic drug use ultimately produces cellular and molecular adaptations in higher-processing areas of the brain, leading to disruptions in learning, mood, inhibitory control, and many other functions.
As it became more and more prevalent in the early twenty-first century, social media became an area of advanced scrutiny for researchers, particularly regarding its addictive qualities and effect on dopamine production in the brain. At the same time, social media was examined for its adverse effects on adolescents’ mental health, with Dr. Vivek Murthy, the US surgeon general, calling for the addition of warning labels to social media platforms in 2024.
Bibliography
Barry, Ellen, and Cecilia Kang. "Surgeon General Calls for Warning Labels on Social Media Platforms." The New York Times, 17 June 2024, www.nytimes.com/2024/06/17/health/surgeon-general-social-media-warning-label.html. Accessed 9 July 2024.
Brookshire, Bethany. "Dopamine Is. . ." Slate. Slate Group, 3 July 2013. Web. 28 Oct. 2015.
Trafton, Anne. “How Dopamine Drives Brain Activity.” McGovern Institute for Brain Research, 1 Apr. 2020, mcgovern.mit.edu/2020/04/01/how-dopamine-drives-brain-activity/. Accessed 22 Nov. 2022.
Kipper, David, and Steven Whitney. The Addiction Solution. New York: Rodale, 2010. Print.
Koob, George F., and Nora D. Volkow. “Neurocircuitry of Addiction.” Neuropsychopharmacology 35 (2010): 217–38. Print.
Nutt, David J., et al. "The Dopamine Theory of Addiction: 40 Years of High and Lows." Nature Reviews Neuroscience 16 (2015): 305–312. Print.
Renner, John A. Jr., and E. Nalan Ward. “Drug Addiction.” Massachusetts General Hospital Comprehensive Clinical Psychiatry. Eds. Theodore A. Stern et al. St. Louis, MO: Mosby, 2008. Print.