By Sudiksha Dixit
How many of you tell yourselves you will keep scrolling on tiktok for just 5 more minutes and it turns into another hour?
Addiction can be as small as scrolling on your phone, to as big as substance abuse. Today it is one of the most complex health problems worldwide, with no known cure and many neuroscientists still trying to figure out the mechanisms of the disease. So what actually is it?
According to the NHS, addiction is defined as ‘not having control over doing, taking or using something to the point where it could be harmful to you.’ [1] When we think of addiction, we commonly associate this to drugs, smoking, alcohol or gambling. However, you can be addicted to countless things such as social media (tiktok), shopping, work or even video games. People crave the high that doing a certain activity can give, and once they stop, withdrawal symptoms kick in, urging the person to carry on with that activity to prevent feeling the low withdrawal causes. This develops into a routine habit progressing into something you can’t live without, leading to harmful consequences not only to yourself, but also to the people around you. In recent years, it has been classified as a chronic mental disease.
The mesolimbic dopamine system, otherwise known as the reward pathway of the brain, consists of a network of brain structures including the basal ganglia, the extended amygdala and the prefrontal cortex. The reason why our reward pathway is called the ‘mesolimbic system’ is because the dopamine released here is from the midbrain and it travels to the limbic system. It is activated in association to rewards.
The basal ganglia controls the pleasurable effects of addiction, as it sends signals to individuals telling them to continue their addictive habits. Not only is the basal ganglia involved in smooth body movement and coordination, but it also plays a major role in habitual formation of substance usage and routine behavioural patterns. It has two main subsections: the nucleus accumbens and the dorsal striatum. The mesolimbic pathway consists of neurons that produce dopamine in the VTA (ventral tegmental area) which are then projected to the nucleus accumbens. The nucleus accumbens then releases and activates the neurotransmitter dopamine, causing an increase in dopamine levels. It is involved in processing rewarding stimuli (such as food, social interactions and exercise) and it mediates positive reinforcement for natural rewards or for seeking natural rewards like food, sex or other substances. The second subsection, the dorsal striatum, plays a key role in habit formation and the development of addictions.
The extended amygdala plays a role in the feelings that one experiences with withdrawal like uneasiness, instability and anxiety. It is involved in processing the emotional value of stimuli - if there is a threatening stimulus present, then the amygdala is involved in identifying it as a threat and coordinating with the hypothalamus to initiate a fight or flight response. It interacts with the hypothalamus, which controls the activity of many glands like the pituitary, which release hormones that regulate metabolic processes in our body.
The prefrontal cortex is involved in the control of executive functions - this includes a set of cognitive processes like impulse control, time management, organisation and regulation of emotions. The prefrontal cortex regulates thoughts and emotions through connections with other parts of the brain, as these cognitive functions are very complex.
So when someone uses cocaine or plays a video game, dopamine levels increase, causing a surge of satisfaction. This surge is what is associated with using, which reinforces the use of the substance/activity, increasing the likelihood for the person to use again. Over time, the more a person uses a substance/activity, the brain becomes less sensitive to the rush of dopamine, as the brain’s circuits alter and a tolerance is built. This results in a person doing more of the substance or activity to achieve the same satisfaction only a small amount of the substance would have produced previously. This results in a cycle of addiction and has irreversible consequences to the brain, as it could change the shape of parts of the brain like the prefrontal cortex, where impulse control could be reduced, leading to the progression of addiction.
When a person is addicted to something, they may go through stages in the cycle of addiction. Generally, there are around 4 to 5 stages which are:
Initial use: This is when it is a person's first time being exposed to a substance or activity. They experience a surge of euphoria, causing some to chase the ‘high’ the activity gives them. There are risk factors that play a part in how likely a person is to get addicted to something, especially substances. This includes:
Genetics - if people in your family have experienced addiction, you are more prone to it, especially substances.
Exposure (especially during adolescence) - when one is exposed to addictive substances at a young age, it has an impact on brain development leading to the person being more likely to be mentally ill and allowing their addiction to progress
Sex - There are differences in the brains of males and females - despite women being less likely to use drugs, they feel the effects of substances more than men and are more likely to get addicted to them
Type of substance used - Nicotine and opioids are more addictive due dopamine flooding the pathway 10 times more than natural rewards. As well as this,injecting a substance is more likely to cause an addiction than swallowing, as the substance goes straight to your bloodstream and to the brain, instead of going through internal organs like the liver and kidney, where the substance is filtered first.
Abuse: A person may start doing an activity or substance regularly as they enjoy the satisfaction the activity gives them.
Tolerance: This is when the substance has changed the shape of the brain, meaning that more of the substance or activity is needed to have the same effect on the person as it had when they first started using.
Dependency: At this stage, withdrawal symptoms can kick in, and the person feels as if they need to do the activity or substance in order to avoid the unpleasant effects of withdrawal like nausea and psychological distress.
Addiction: After a period of time, some people realise that they can’t function without doing the activity or substance. This can lead to deteriorating personal relations, financial instability, poor performance at work/school, the person abandoning their routine and changes in their personality.
According to new research by The Forward Trust, ‘45% of UK adults aged 18-75 have either directly experienced addiction themselves with a dependency to alcohol, drugs, medication, gambling or sex, themselves, or know someone close to them that has’.[2] The healthcare community has come a far way in recognising how formidable a threat addiction is, with billions being invested into understanding the complexity of the disease and ways to prevent it worldwide. However, there is a lot more that neuroscientists still haven't figured out including the involvement of other structures in the brain and how they play a part in addiction in order to find a cure. Despite colossal efforts from clinics, anonymous support groups and charities, there needs to be a lot more done within communities about the stigma addiction brings, allowing people to speak out and seek help.
If you or someone you know may be addicted to something, the link below provides plenty of contacts to help support those who may need it.
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