The Science of Addiction

How powerful can addictions be?

How powerful can addictions be?

Addiction is defined as “not having control over doing/taking or using something to the point where it could be harmful to you”.

Addiction, is one of the worst diseases that affects humans in my opinion. This is because addiction turns you against yourself, it renders you powerless to do anything you want to do, and it leaves you as a prisoner in your own body. Most people, that undergo some sort of addiction, change in some form or manner by allowing their addiction to govern their lives. For example, a smoker would take breaks from work to relieve themselves, or a heroin user may steal money and commit crimes to fund their addiction.

But what substances could cause a person to be addicted? Well, contrary to what many people think, there are many substances other than drugs that can lead to addiction, such as work (workaholics), shopping, sex or even the internet.

But all of these substances/actions have one thing in common, they all have something to do with neurotransmitters. Neurotransmitters, also known as chemical messengers are chemicals that transmit signals across a chemical synapse, such as between neuron cells or between neurons and muscles/gland cells. When there are neurotransmitters, there will always be a neuroreceptor, which is ‘activated’ when a specific neurotransmitter reaches it. But in terms of drugs, the main neurotransmitters involved are those that have something to do with pleasure, such as dopamine or endocannabinoids. For example, some drugs simulate neurotransmitters, such as heroin or marijuana, and some drugs can cause the excessive release of the pleasure neurotransmitter, dopamine, such as cocaine or methamphetamine.


Addiction to drugs has been a rising major concern in today's society.

Addiction to drugs has been a rising major concern in today's society.

In the case of cocaine or methamphetamine, excessive amounts of dopamine are released when they are taken, and they are said to affect our brain’s ‘reward circuit’ (the same circuit referred to in my previous article about processed food). But what makes these drugs so addictive? They are addictive because when the brain’s reward circuit is triggered, (by drug usage, or a general pleasurable activity), it remembers this activity and will teach us to repeat it again and again. But when very high quantities of dopamine are released at one time, i.e. unnatural levels, found when drugs are taken, the brain essentially teaches us to ‘really’ repeat the activity, again and again.

But this is just the start of addiction. After a while, your brain adjusts to the high surges in dopamine. This is done by either, producing less dopamine each time, or producing less dopamine receptors. But in both cases, the result will be that less dopamine is signalled in the brain. this means that a person’s dopamine levels are much lower than those of a non-addict.

Thus, resulting in the person feeling depressed permanently, and they require the drug just to bring their dopamine levels back to normal. This is called tolerance, and the longer you take a drug (could even be coffee or gambling), the more tolerant you will get to it, and say if it is a toxic drug, if you have to take much more to get the same ‘high’, there is a much higher chance of dying, which is the reason, why most drug users die after prolonged periods of drug abuse, and not straightaway.

Addiction can also have a more permanent effect on your brain, as it can physically affect the structure and function of it, and this is why addiction is formally known as a “disease”.

But why are some drugs much more addictive than others? For example, heroin is much, much more addictive than a drug such as marijuana, which has a much smaller addictive effect. Well, the addictive power of a drug could be down to different reasons, one of which is the time it takes to arrive in the brain. for example, if something is smoked or injected, it will reach the brain much quicker than if something is chewed (and spat), or swallowed. This is due to the fact that if something occurs more quickly, your body will associate that rewarding feeling much more with the drug, and thus make you long for it more.


Addictions affect the body in various but distinctive ways.

Addictions affect the body in various but distinctive ways.

Also, the addictiveness depends on the severity of the withdrawal symptoms once the drug usage has stopped. For example, cocaine has a short lasting, powerful effect, with high withdrawal symptoms, making it very addictive. Finally, the addictiveness of the drug depends on what neurotransmitter it effects. This is why cannabis, which simulates neurotransmitters of the endocannabinoid type, is not as addictive, as these neurotransmitters do not really mess with your body’s reward system.

But heroin, which stimulates an opioid, is very highly addictive, as these opioid neurotransmitters are only naturally released by the body in times of great, great pain, but unlike morphine (also an opioid) heroin works very fast due to its solubility in fats, which results in its ability to pass through the membranes in our body/brain quickly. This makes it one of the most addictive drugs in existence.

Finally, what really interested me was the story of US soldiers in Vietnam, during the Vietnam war. In this war, around 15% of the American soldiers became addicts to the highly addictive heroin. The soldiers that were clean were allowed to return home, but the addicts (found by urine test) were ‘dried out’ of heroin. But the story takes an interesting turn, when they returned home, as around 95% of those that became addicted in Vietnam, were not addicted any more when they returned home. This is quite an amazing feat, seeing as how addictive heroin can be.

This ‘feat’ can be explained by simple psychology, and also autonomy (see my previous article). For example, the soldiers were so used to using the heroin in the environment of Vietnam that it just became an autonomous action, and the action of taking heroin may have been associated with a familiar place, such as a bunker/army base. But in the USA, there were no cues to make them want to take it.

This is the same concept of an office worker feeling the urge to smoke when he sees the entrance to his office, a place where he always smokes. In this case the office entrance works as a powerful mental cue for him to smoke, and will cause the person to smoke even if he doesn’t feel the ‘urge’ to smoke. So, in the case of the soldiers, the fact that there were not any more cues for them to be reminded to take heroin, resulted in their addiction ‘wearing away’.

This shows how our body’s main weakness, is essentially…. our body. As manufacturers will take every opportunity to exploit a weakness in our body, to tailor products so that they are highly addictive. whether it may be a processed food, or highly dangerous synthetic cannabinoids, I think that it is sickening how far people will go to make a profit.