Chapter 2: The Neurochemistry and Physiology of Addiction

By the end of this chapter, you should be able to:

  • Define the characteristics of the major classes of drugs. (LO2)
  • Identify and summarize the addiction process and the characteristics thereof. (LO3)

Addiction is Subjective

Each person has their own genetic and environmental risk factors that account for roughly have of an individual’s risk for developing an addiction (Chakroborty, et al., 2016; Lazzara;). Even those who have a relatively low risk of genetic factors, may be susceptible with repeated exposure to high doses of an addictive drug. (CDC, 2022) and their related proteins are the key components through which environmental factors can affect the genes of an individual. They are also responsible for environmental influences on genes, meaning behavioral responses to environmental stimuli. In addiction, epigenetic mechanisms play a central role in the pathophysiology of the disease. More research is needed to know the extent to which these genes play a role in addiction and the corresponding behaviors (Herman & Roberto, 2015; Lumen).

For more on the neurochemistry and addiction, please watch these videos.


The Cycle of Addiction

Addiction is describe as the repeating cycle of three stages (shown below; select the double pointed arrow in the lower right corner to expand the graphic to full screen). Each stage is particularly associated with one of the brain regions (basal ganglia, extended amygdala, and prefrontal cortex) (APA, 2022; Fudge & Emiliano, 2003; Lipton, et al., 2019; Shackman, 2016). This three-stage model draws on decades of research and provides a useful way to recognize the cycle of addiction.

  • Basal Ganglia: Involved in the Binge / Intoxication Stage
  • Extended Amygdala: Involved in the Withdrawal / Negative Affect Stage
  • Prefrontal Cortex: Involved in the Preoccupation / Anticipation Stage

Theories of Addiction

Several theories or models of addiction are studied and emphasized in the world of addiction. We will be covering the following in the remainder of this chapter as well as some influencing factors.

  • Addictive Disease Model
  • Behavioral/Environmental Model
  • Academic Model
  • Diathesis Stress Theory of Addiction

Addictive Disease Model

The disease model of addiction compares and contrasts the differences between those who have an addiction and those that do not. This theory defines addiction as a disease that changes the brain structure and functioning (Butler Center for Research, 2021). This model considers addiction a disease that can never be “cured”. This is strongly related to the slides provided that discuss the different brain structures affected by addiction (Racine, et al., 2017)

Recovery, from this perspective means that the recovering person must always refrain from use or connection to addictive substances and activities. Abstaining from these activities can be very challenging, so the theory recommends a support group, usually comprised of peers. A well-known example is Alcoholics Anonymous. It is a group of people struggling with the same addiction to alcohol. They can better understand and support each other because they too are struggling with the addiction.

Behavioral/Environmental Model

Research suggests that environmental factors my affect substance abuse behaviors. Factors that can promote abuse behaviors can include access and exposure, racial and socioeconomic status, and barriers to treatment. If you think back to Chapter 1, and the mention of psychological reasons for addiction, this paired with environmental triggers could promote addictive tendencies. There is research to support the idea that these behavioral and environmental barriers impact addiction, but ultimately more research needs to be done to discover the where, why, and how these affect a person (Surgeon General).

Academic Model

This model was proposed by C.K. Himmelsbach in the early 1940s. This model revolves around . This model suggests that pleasure, salience, and withdrawal are all linked to allostasis in addictive scenarios (De Ridder, et al., 2016; Olney, et al., 2018). For example, originally, it was thought that the amount of pleasure an addicted person experiences, decreases over time and requires increased amounts of the substance (tolerance). But more recently, research suggests that allostasis is a normal response to maintain stability when the parameters for normal functioning are outside the “normal” range and thereby resets those parameters.

Diathesis-Stress Model of Addiction

The diathesis-stress model combines biology and psychology to predict the predisposition of a disorder (Berridge & Robinson, 2016). This ultimately suggests that people are predisposed to be a certain way when faced with stressors, like trauma, life events, abuse, etc. It’s not always just biological, it can also be psychological. The key components of this model as the the predisposition (diathesis) and the stress must be present for the disorder to occur.

Other Addictions

There are other addictions beyond substances like cocaine or alcohol. These can include gambling, eating, sex, pornography, computers, video games, social media, exercise, and shopping. By no means is this an exhaustive list, but it does mention a fair number that might be pertinent in your life. The “drug” of choice, be it alcohol or gambling (Gorzelanczyk, et al., 2021) is typically . The goal may be affected by the stress and withdrawal experienced by the user. Typically, individuals differ in their experience of value, due to their different risk factors. The end result, however, is that the individual experiences a minimized negative state when participating in these situations, accomplishing their goal. Below are some optional studies and information related to non-drug addictions (Szerman, 2020).

Anonymous Organizations

Below is a short list of “Anonymous” organizations that support those with addiction; these are 12-step programs. Review them as they are relevant to you.


Addiction Policy Forum (2019, May 2). The disease model of addiction [Video]. YouTube.

American Psychology Association (2022). Basal ganglia. APA Dictionary of Psychology

Berridge, K. & Robinson, T. (2016). Liking, wanting, and the incentive-sensitization theory of addiction. American Psychology, 71(8), 670-679, doi: 10.1037/amp0000059

Butler Center for Research (2021). The brain disease model of addiction. Hazeldon Betty Ford.

Center for Disease Control and Prevention (2022). What is epigenetics. Genomics and Precision Health.

Chakraborty, J., Grineski, S., & Collins, T. (2016). Risky substance use environments and addiction: A new frontier for environmental justice research. Int J Environ Res Public Health, 13(6), 607, doi: 10.3390/ijerph13060607

De Ridder, D., Manning, P., Leong, S., Ross, S. & Vanneste, S. (2016). Allostasis in health and food addiction. Scientific Reports, 6,

Fudge, J. & Emiliano, A. (2003). The extended amygdala and the dopamine system: Another piece of the dopamine puzzle. Journal of Neuropsychiatry and Clinical Neuroscience, 15(3). doi: 10.1176/jnp.15.3.306

Gorzelanczyk, E., Walecki, P., Blaszczyszyn, M., Laskowska, E., & Kawala-Sterniuk, A. (2021). Evaluation of risk behavior in gambling addicted and opioid addicted individuals. Frontiers in Neuroscience,

Herman, M. & Roberto, M. (2015, March 19). The addicted brain: Understanding the neurophysiological mechanisms of addictive disorders. Frontiers in Integrative Neuroscience, 9(18), doi: 10.3389/fnint.2015.00018.

Lazarra, J. (n.d.) Introduction to psychology. Pressbooks.

Lipton, D., Gonzalez, B., & Citri, A. (2019) Dorsal striatal circuits for habits, compulsions, and addictions. Frontiers in Sytems Neuroscience, 13(28), doi: 10.3389/fnsys.2019.00028

Lumen Learning (n.d.) Abnormal psychology. Lumen.

Olney, J., Warlow, S., Naffziger, E., & Berridge, K. (2018). Current perspectives on incentive salience and applications to clinical disorders. Curr Opin Behav Sci, 22, 59-69, doi: 10.1016/j.cobeha.2018.01.007

Professor Dave Explains (2019, December 27). Drug addiction and the brain [Video]. YouTube.

Racine, E., Sattler, S., & Escande, Al (2017). Free will and the brain disease model of addiction: The not so seductive allure of neuroscience and its modest impact on the attribution of free will to people with an addiction. Frontiers in Psychology, 8, 1850, doi: 10.3389/fpsyg.2017.01850

Shackman, A. & Fox, A. (2016). Contributions of the central extended amygdala to fear and anxiety. Journal of Neuroscience, 36(31), doi: 10.1523/JNEUROSCI.0982-16.2016

Stoddart, T. (2011) List of 12 step programs. SoberNation.

Surgeon General (n.d.) Neurobiology. Surgeon General.

Surgeon General (n.d.) The surgeon general’s report. Surgeon General.

Szerman, N., Ferre, F., Basurte-Villamor, I., Vega, P., Mesias, B., Marin-Navarrete, R., & Arango, C. (2020). Gambling dual disorder: A dual disorder and clinical neuroscience perspective. Frontiers in Psychology, 11, doi: 10.3389/fpsyt.2020.589155


Icon for the Creative Commons Attribution 4.0 International License

Psychology of Addiction by Andrea Bearman and Adelle Schwan is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

Share This Book