International scientific literature affirms almost unanimously that addiction is a serious and chronic brain disease that is genetically determined to a considerable degree. The susceptibility or likelihood to develop an addiction is said to be genetically determined by 30 to 60%. Addiction involves a large number of genes related to, among other things, impulsivity, anxiety, mood regulation and sensitivity to stress. Even genes that affect the metabolism of alcohol or drugs can play a role in addiction.
A closer look at addiction
Addiction behaviour is the result of profound and long-term changes in the brain. The key symptom of these changes is the recurring desire to look for or to use drugs or alcohol, even after years of abstinence and despite the extreme, adverse effects. In other words, someone who has been an addict will remain vulnerable to a relapse. Extensive research has demonstrated that regular exposure to addictive substances will lead to a range of far-reaching neurochemical changes in the brain. When the substance is used for the first time, it is often a fun and pleasant experience. This feeling of a high or a rush is caused by the direct or indirect intense stimulation of the dopamine reward circuitry in the brain. This reward circuitry is a neuroanatomical structure in which the reward behaviour originates. This behaviour is aimed at achieving natural objectives, such as eating, drinking and procreation in view of increasing the chances of survival. Achieving these objectives is linked to a sense of pleasure, fun and satisfaction and is reinforced through repetition. In other words, people are motivated to act on this behaviour again and again to increase their chances of survival. It is a well-known fact that all addictive substances directly or indirectly affect the reward circuitry due to their chemical structure. Using the substance is therefore perceived as a rewarding act. This is referred to as the process of LIKING.
Increased use of the substance
Repeated use of addictive substances will lead to reduced activity and sensitivity in the dopaminergic system over time. This reduces the pleasant, rewarding effect of the substance and will motivate the user to increase the amount of the substance used in order to achieve the same effect. Furthermore, there is an increased motivation (craving) to use the substance again. Natural rewards are no longer perceived as rewarding. Addicts may start ignoring their basic needs. On the other hand, abstinence from the substance will eventually lead to the partial recovery of dopaminergic activity. Natural rewards will regain their effect thanks to the increase in dopaminergic activity and the craving for the substance will gradually decline. This recovery process may take more than a year to be completed.
Drug-seeking behaviour
The next stage involves a compulsive and automatic behavioural sequence with the purpose of obtaining the substance, or in other words, drug-seeking behaviour. To a considerable extent, this behaviour is controlled and regulated at a subconscious level. The behavioural sequence becomes ‘automatic’ and can be activated subconsciously and/or without exposure. The use of the substance is acquiring a more compulsive nature. In addition, this behavioural pattern goes hand in hand with a strong focus on the substance and all the stimuli that are directly or indirectly related to it. This is how the addicted brain will get better at predicting the likelihood of finding the addictive substance in certain situations. The addict will become more adept at looking for and finding the substance. Stress can also play a role in activating this behavioural pattern.
Control mechanisms and the risk of relapse
Despite the above, this automatic behaviour can be consciously controlled. However, these control mechanisms in the brain are slower and less efficient. When the control mechanism is overpowered by the strong presence of stimuli, the control mechanism will fail and the automatic behavioural sequence will prevail. This is when the risk for a relapse arises. The neurochemical changes are likely to be of a long-term nature and are affected by abstinence to a limited degree. This explains the phenomenon where users of addictive substances are at risk of a relapse even after many years of abstinence.
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