Last week I analyzed the processes that cause addiction to form and the different ways in which drug use affects the transmission of neurotransmitters within our synapses. I will be continuing the topic of addiction for this week as I discuss how addiction relates to mental health disorders. This blog will be a direct continuation of where my previous blog left off at. First, however, before I begin, I must include the third process for which addiction can develop considering that it was not included in last week’s blog post.

The third and final method for which neurotransmission is disrupted is unique in its own way compared to the previous two. While the two previously mentioned processes enhance or strengthen the signal being transmitted, this method utilizes inhibitory neurotransmitters to reduce the intensity of sent signals. That means that instead of cascading positively charged ions, negatively charged ions are being transmitted. The two previous processes are a lot like the gas pedal on a car; they make it go forward. As opposed to this, inhibitory neurotransmission resembles the brake pedal since it causes the signal to stop or slow down. The most prevalent inhibitory neurotransmitter in the human body is GABA which essentially functions as a sedative. Alcohol is one such example of a drug that increases the effects of GABA within the neuron and causes the individual to fall into a narcotic state. Alcohol essentially serves as a GABA imitator allowing its molecules to bond with the adjacent neuron’s receptors and pass down the negated signal.

These three main processes are the ways in which drugs affect our brains. Over time, as individuals consume these harmful compounds, our brain learns to decrease its production of dopamine, thereby creating a dependence on the said drug in order to experience the same level of pleasure felt before. Due to this, the person’s ability to naturally experience pleasure also becomes reduced as the brain is no longer able to produce dopamine by itself. Individuals who misuse drugs then begin to lack motivation as they are now unable to enjoy the things they had previously found pleasurable. They need to continue to take drugs to experience even a normal level of reward, only adding to the addiction cycle. Eventually, even the feelings that the drugs used to impose become diluted as the receptors at which they interact are now unable to perfectly bond together, making them less and less efficient in transcribing a dopamine signal. This is commonly known as the tolerance effect.

However, it is when addicts eventually strive to overcome this effect and receive treatment do they actually realize how difficult it is to break this cycle. The brain requires a lengthy period of time to reacclimate to having to produce its neurotransmitters again. This period is commonly known as withdrawal and is characterized by the patient feeling a diverse range of symptoms depending on age, race, socioeconomic factors, as well as what drugs were used and for how long. Withdrawal may cause recovering addicts to develop insomnia, depression, anxiety, fatigue, and nausea as it is the first but necessary step in the recovery process. The process, however, can be incredibly dangerous if not regulated in a professional setting and under medical supervision. The patient must gradually decrease the usage of their addictive substance in order to allow the brain to adjust in the safest way possible. Addiction quite literally changes the chemical structure and processes of the brain and directly degrades the ability of individuals to develop motivation, making it all the more difficult for them to receive treatment. It is because of this reason that intervention is necessary to treat addiction and prevent drug overdoses from occurring in the future.

Now after having looked at the processes by which addiction forms and how it can be treated we can finally begin to understand the comorbidity between substance use disorders and mental illness. Approximately 25% of individuals who have a mental illness also consecutively face a substance use disorder, however, it is important to note that correlation does not necessarily mean causation. There is evidence from several studies that link both types of disorders together, but there are three ways in which they can possibly relate and be diagnosed.

The first way is that both substance use disorders and mental illnesses can arise from the same environmental risk factors. Genetics, for example, plays a large role in determining the strength at which dopamine may be produced or transmitted, as those who are predisposed to feeling a heightened level of pleasure from certain drugs might be more likely to develop a substance use disorder for that drug. At the same time, however, genetics can also influence mental disorders and make individuals more likely to develop genetically associated illnesses such as ADHD, schizophrenia, and bipolar disorder. Past trauma and stress from childhood events can also serve as risk factors for both disorders as an early indication of antisocial behavior and exclusion can lead to both drug use as well as mental illness. For example, the season of summer may cause a sudden surge in both the ice cream industry as well as the swimwear market. However, it’s not possible to conclude that the increase in popularity within the ice cream market led the swimwear market to increase. The same goes for substance use disorders and mental illnesses. Even though both might develop at the same time, we cannot conclude that one causes the other simply because of the numerous factors at play that scientists have so far been unable to manipulate and isolate.

That is where I think I’ll end off for the week. I plan to continue where I left off for our next blog post as I finish analyzing the other two ways in which addiction and mental health disorders relate. We’ll see if that ends up being my final iteration of this neuroscience series or not and if I find anything else interesting as I’m doing my research. Thanks for reading!