We are intrinsically motivated to do the things that make us feel good by triggering our brain’s reward system, a group of structures in place that responds to rewarding stimuli like food, sex and drugs such as cocaine and alcohol. Rewarding stimuli such as these promote the release of a brain chemical called dopamine, which makes us feel good so that we are motivated to repeat certain behaviors that are important for our survival. However, the ability of addictive drugs such as cocaine to act on dopamine receptors contributes to its high potential for abuse and dependence.
Drugs and dopamine
Dopamine release is affected in people who are addicted to drugs, according to a 2008 paper by Nora D. Volkow, M.D., director of the National Institute on Drug Abuse (NIDA), and her colleagues. Volkow and her colleagues’ review of the literature implicated the decrease in dopamine activity and deregulation of the striatum and prefrontal cortex in the compulsive use of drugs and loss of control experienced by individuals with substance use disorders. Volkow and her colleagues suggested that marked reductions in dopamine D2 receptors and striatal dopamine are associated with the repeated release of dopamine due to the use of addictive drugs. These reductions are further associated with altered activity in the following areas of the brain that are responsible for executive function (dorsolateral prefrontal cortex), inhibitory control (cingulate gyrus) and reward salience and making decisions (orbitofrontal cortex).
Together, the impaired activity in these areas of the brain can make it difficult for someone to control compulsions, impulsivity and intentional actions. Studies using position emission tomography (PET) and functional magnetic resonance imaging (fMRI) indicate that the rapid release of dopamine occurs from the intravenous administration of stimulant drugs. Initially, individuals who abuse addictive substances experience heightened dopamine release. Over time though, the repeated use of addictive stimulant drugs can increase the threshold for dopamine to be activated and released, which can cause individuals to take more of a drug to achieve the desired effect.
Dopaminergic deficits in individuals with cannabis use disorders
Researchers recently investigated whether the dopaminergic deficits exhibited by individuals with addictions to cocaine and other addictive drugs were also present in individuals with cannabis use disorders. The release of dopamine from the striatum was investigated in 11 patients with cannabis use disorders and 12 healthy controls in a new study funded by the National Institute on Drug Abuse (NIDA). Participants with cannabis use disorders did not have a co-occurring psychiatric disorder.
PET scans were completed before and after the researchers administered d-amphetamine orally to patients. The results of this study showed that lower dopamine was released in the striatum in the participants with cannabis use disorders. Lower dopamine release in the striatum was associated with negative symptoms such as inattention in the participants. Similar to other addictive drugs, the researchers suggested that dopamine release in the striatum was affected by those with cannabis use disorders.
Substance use disorders can have negative consequences on the health and well-being of patients. As one of the leading providers of addiction and behavioral health treatment, Sovereign Health of Florida incorporates a holistic approach and evidence-based treatments into our treatment programs for patients with substance use disorders, mental illness and co-occurring disorders. Contact our 24/7 helpline to learn more about the programs offered at Sovereign Health.
About the author
Amanda Habermann is a staff writer for Sovereign Health. A graduate of California Lutheran University, she received her M.S. in clinical psychology with an emphasis in psychiatric rehabilitation. Her master’s thesis was written on “The effect of parental codependency on elementary school children’s social and emotional development,” and her research has been accepted for poster presentations at the Western Psychological Association. She brings to the team her extensive clinical background and skills in psychological testing and assessment, clinical diagnosis, research and treatment, and recovery techniques for patients with mental illness. She is a passionate researcher and enjoys staying up to date on the newest topics in the field. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.
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