Tara Doraiswamy
In the field of clinical psychology, there are a few different broad approaches towards mental illnesses. These approaches provide a framework that guides the understanding of the causes, maintenance, and treatment of various disorders. Addiction, in particular, is an illness that is increasingly gaining relevance. Drug addiction and substance abuse disorders are related to the biological, psychological, and environmental forces acting on an individual. This post will focus on neuroscience under the biological approach, and the behavioural approach. It is important to clarify that as per the DSM-5, substance abuse disorders involve patterns of symptoms related to excessive and harmful usage of substances, which may manifest to an extreme form called addiction. Notably, addiction is not an assured consequence of substance use. The individual’s genetic predisposition, socioeconomic background, cultural environment, exposure to stress, social support, and psychological history and condition play important roles in predisposing an individual to addiction, or providing buffers for the same (General & Human Services, U.S. Department of Health and, 2017).
Neuroscience provides a crucial perspective of addiction that informs much of the present understanding and treatment. This is because sustained drug use greatly affects the neuronal circuits which are involved in reward pathways, conditioning to the drug, brain activity, and withdrawal patterns. Most drugs provoke a euphoric sensation by stimulating dopamine bursts in the dopaminergic mesolimbic, or reward, pathways. This release of dopamine, which is primarily involved in pleasure, reinforces further use of the drug, strengthening the association between the stimuli associated with the drug and the expectation of drug-induced pleasure. Other neurotransmitters like opioids, cannabinoids, GABA, serotonin are also involved to varying levels depending on the drug.
There are three main stages that comprise the addiction cycle, namely intoxication, withdrawal, and anticipation, all of which are linked to each other. In the anticipation stage, the drug cues (presentations of drug-related stimuli such as people, places, drug paraphernalia, and even internal states, such as mood—with the substance's rewarding effects) themselves cause release of dopamine in the striatum, motivating the individual to seek and consume the drug (Volkow, 3). This pattern, unless broken, gets strengthened through increased conditioning of the drug cues, and thus results in maintenance of the addiction. It is widely known that drug addiction is to affect brain functioning, particularly the prefrontal cortical circuits which are responsible for executive functions like rational decision making, reasoning, emotion regulation etc (Volkow & Boyle, 2018). In the brain of an addict, these prefrontal cortical circuits are hypofunctional due to repeated drug usage. This leads to an impairment in the ability to use executive skills to fight the urge to use the drug despite knowing its negative effects, as a healthy individual would be able to. As the individual builds tolerance for the drug, the positively reinforcing effects of substances tend to diminish with repeated use, and the drug may simply be taken to alleviate the negative symptoms of withdrawal, thus becoming a negative reinforcer. This may lead to use of the substance in greater amounts and/or more frequently in an attempt to experience the initial level of reinforcement. Alongside increased tolerance for the drug, individuals struggling with addiction usually experience decreased sensitivity to non-drug rewards, as a result of which activities that were once pleasurable no longer yield much pleasure.
The second approach is the behavioural approach. Although fundamentally different from the neuroscience approach, there is wide scope for integrating behavioural models in the understanding and treatment of addiction disorders. The main argument of the behavioural approach, in the context of addiction, is concerned with the fact that it involves repeated and immoderate choice of a drug over other reinforcing stimuli in the environment, due to it possessing greater reinforcing capacity as compared to other reinforcers available to the individual (Winger et al., 2005). The drug seeking and consuming behaviours eventually dominate the behaviour repertoire of the individual. It is also to be noted that this is often strengthened when alternate sources of reinforcement or pleasure are limited to the individual. An advantage of this approach is the fact that it posits an explanation for why youngsters who engage in excessive drug use are likely to reduce usage as they grow older. The behavioural explanation to this is that it may be due to alternate reinforcers like marriage, family and employment which are not sufficient reinforcers at a young age to detract from drug consumption. People who fail to find these alternate sources may find it more difficult to undergo the process of “maturing out” of the addiction (Winger et al., 2005).
When considering the behavioural approach is it important to consider that it is vastly under researched as compared to the neuroscience and genetics of addiction. As work progresses on creating treatment and preventative strategies for addiction, an integrated view on addiction, combining the vast knowledge on the neural circuitry and brain function with the behavioural perspective would be valuable. The behavioural approach tends to be more hopeful about treating addiction as opposed to the neuroscience approach as it emphasises the possibility of alternate reinforcers or rewards that replace the dependence on the drug (Winger et al., 2005). This, in tandem with the neuroscience and medicinal approaches, would inform a more robust and holistic view to treatment.
References
General, O. O. T. S. & Human Services, U.S. Department of Health and. (2017). The Neurobiology of Substance Use, Misuse, and Addiction. In Facing Addiction in America: The Surgeon General’s Report on Alcohol, Drugs, and Health (p. 27). CreateSpace Independent Publishing Platform.
Volkow, N. D., & Boyle, M. (2018). Neuroscience of Addiction: Relevance to Prevention and Treatment. American Journal of Psychiatry, 175(8), 729–740. https://doi.org/10.1176/appi.ajp.2018.17101174
Winger, G., Woods, J. H., Galuska, C. M., & Wade-Galuska, T. (2005). BEHAVIORAL PERSPECTIVES ON THE NEUROSCIENCE OF DRUG ADDICTION. Journal of the Experimental Analysis of Behavior, 84(3), 667–681. https://doi.org/10.1901/jeab.2005.101-04
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