In neurobiology, reward is a positive effect produced on a user by an object or a condition. Reward is associated with a tendency to repeat an action that leads to the reward. The most important center of the reward system is the mesolimbocortical dopamine system. The mesolimbic system projects from dopamine (DA) neurons in the ventral tegmental area (VTA) to the nucleus accumbens (Garrett & Hough, 2018). The mesocortical system projects from DA neurons in the VTA to the frontal cortex. Rewards are associated with increased dopamine levels after stimulation of the reward system.
Addictive substances or behaviors have a significant impact on the mesolimbocortical dopamine system. First, the dopamine activity in the brain decreases, which causes a reduced response to normal rewards, such as food, sexual contact, or warmth (Garrett & Hough, 2018). At the same time, drugs and behaviors cause an increased reaction from the dopamine system (Garrett & Hough, 2018). Second, addictions often cause hypofrontality, which is a reduced activity of the prefrontal cortex, anterior cingulate cortex, and orbitofrontal cortex (Garrett & Hough, 2018). Finally, the long-lasting effect is caused by learning, which is promoted by glutamate that remodels synapses (Garrett & Hough, 2018). Therefore, additions are not just inappropriate habits, but neurological conditions that lead to lifelong changes in the brain. For instance, cocaine administration causes a short-term rise in the dopamine level, which causes a sense of euphoria, loss of control, and compulsive responses (Nestler, 2005). Cocaine affects the nucleus accumbens by producing enormous amounts of dopamine, which causes a powerful feeling of pleasure (Nestler, 2005). The memories of such pleasures are imprinted in the hippocampus and amygdala, causing learning and lifelong changes (Nestler, 2005). According to Garrett & Hough (2018), chronic administration of cocaine also increases dendrite length and synaptic complexity in the nucleus accumbens and prefrontal cortex.
Cocaine addiction is treated using various methods, including medications and therapies. Cognitive-behavioral therapy (CBT) is known to have tremendous success in treating cocaine addiction. In particular, McHugh, Hearon, and Otto (2010) report that the CBT has over 60% success rate according to screening 52 weeks after the intervention. At the same time, disulfiram can be used as a medication to treat cocaine addiction. Even though different studies confirm the effectiveness of the drug, there are no medications approved by the U.S. Food and Drug Administration to treat cocaine addiction (Carroll et al., 2016). The success rate of the pharmacological intervention, however, can be improved using CBT (Carroll et al., 2016). Therefore, it is recommended to use an optimal combination of medications and drugs for treating cocaine misuse.
References
Carroll, K. M., Nich, C., Petry, N. M., Eagan, D. A., Shi, J. M., & Ball, S. A. (2016). A randomized factorial trial of disulfiram and contingency management to enhance cognitive behavioral therapy for cocaine dependence. Drug and alcohol dependence, 160, 135-142.
Garrett, B., & Hough, G. (2018). Brain and behavior: An introduction to behavioral neuroscience (5th ed.). Los Angeles, CA: SAGE Publications, Inc.
McHugh, R. K., Hearon, B. A., & Otto, M. W. (2010). Cognitive behavioral therapy for substance use disorders. The Psychiatric Clinics of North America, 33(3), 511–525.
Nestler E. J. (2005). The neurobiology of cocaine addiction. Science & Practice Perspectives, 3(1), 4–10.