…learning and memory, two key elements that affect the likelihood of becoming addicted to something you initially like.

Addiction is a chronic brain disease that involves compulsive use of certain substances despite harmful health effects and social interactions. The person becomes “enslaved by” or “bound to” these substances and as a result it impairs a person’s judgement and emotional wellbeing.

The strong influences they exert on the brain and the whole body are manifested by unique characteristics like:

1. A chronic inability to abstain from a substance or behavior

2. Behavioral impairment/loss of control

3. Craving for these rewarding experiences

4. Diminished recognition of significant problems

5. Emotional response dysfunction

Our perception of addiction has a powerful implication on how our society recognizes and treats a person who is addicted to a substance or behavior. As it has been historically proven, the stigma of mental illness is not easy to be dismissed. It was in 1930 when researchers first began to investigate what causes addiction. They traditionally believed that people who developed addictive behaviors were lacking willpower or had moral impropriety issues. Some others believed that addiction was just an excuse for continuing to use drugs while avoiding the responsibility for the consequences of doing drugs (Carter et al., 2009: 25).

However, neuroscience and brainimaging studies have helped scientists learn more about the complex process. They have presented addictive behavior as a direct result of impairment in our brain’s reward system.

What is the reward system in the brain and how does it work?



The reward system is a group of structures within the brain that are activated by a rewarding stimuli and the most powerful stimuli of this system are drinking, food, sex and social interactions. In a normal person this system reinforces behaviors that are essential for survival, connecting them with a pleasurable feeling. For example: you search for food whenever you are hungry because this system helps you to remember the pleasure that comes with this vital experience.


How is pleasure “encoded” in our brain?

The brain records all pleasures in the same way, whether they originate from alcohol, psychoactive drugs, monetary reward, a delicious meal or a sexual encounter. The compound responsible for this interaction is dopamine, a neurotransmitter released mainly from the nucleus accumbens, a cluster of nerves underlying the cerebral cortex also known as the brain’s pleasure center.

What’s the difference between pleasure and addictive behaviour at the neurochemical level?

Drugs like cocaine, alcohol, opioids like codeine, fentanyl (Actiq,Fentora) or even activities like sex and gambling act in the same manner as natural reward signals except in a much greater degree. The key elements that predispose a certain substance or activity to become addictive are:

  • The speed with which it promotes dopamine release
  • The intensity of dopamine release
  • The reliability of the process
  • The route of administration because it has been determined that taking a drug intravenously as opposed to swallowing it as a pill or smoking it, produces faster and stronger dopamine release

Scientists once believed that the feeling of pleasure associated with the process of taking a pill or performing an activity was enough to cause addictive behaviors. But recent studies indicate that dopamine not only contributes in the experience of pleasure but also plays a significant role in learning and memory, the two key elements that transforms you from liking something to becoming addicted to it.

Practically, what happens after being exposed to a rewarding signal such as eating a favorite food is that dopamine gets released from nucleus accumbens travels to interact with amygdala (area of the brain involved with emotions food was delicious), hippocampus (area of the brain involved in memory formation let’s remember everything about this pleasurable experience: the restaurant I ate it, the person I was with, the color and taste of the food), prefrontal cortex (the area of the brain responsible for planning and executing tasks stay focused on that piece of food ).

Moreover, according to a current theory, which is in the process of being developed, dopamine interacts with another neurotransmitter called glutamate to take over our brain’s reward system.

What happens when we become addicted?

Brain adapts in a way that makes the substance or activity less pleasurable. Dopamine receptors are now overwhelmed and the brain responds by producing less dopamine or by eliminating a great number of dopamine receptors and therefore the neurotransmitter has less impact on our brain’s rewarding system. The same amount of addictive substance or activity as before after a while does not produce the same amount pleasure as before. This phenomenon is known as tolerance.

At this point compulsion takes over. The pleasure associated with the addictive activity subsides, but the memory of the previous effect and the desire to recreate it persists leading to a response craving ‐ whenever the person encounters environmental cues. This response also contributes to relapse after a hard sobriety. For example, whenever a person addicted to alcohol sees a glass of colored drink, a bottle of whisky, he/she might start to drink again.

What causes addiction?

Nobody starts out intending to develop an addiction but many people get caught up without even noticing it. According to World Health Organization (WHO) 240 million people around the world are addicted to alcohol, more than 1 billion people smoke, and about 15 million people use injection drugs such as heroine.

Even though the link between genetics and addiction is still a topic of ongoing debate, studies have shown that genetic predisposition increases the likelihood of an individual becoming addicted by 40-60%. Having a parent with a history of substance abuse increases the risks of developing addiction by 4 times. On the other hand, environmental factors affect the person’s biology and the extent to which genetic factors exert their influence.

Other factors influencing the probability of becoming addicted include:

  • Repeated drug use to relieve stress, improve performance, to feel good or “high”
  • Severe trauma or injury
  • Mental health conditions, especially mood disorders such as chronic anxiety and depression
  • Psychological trauma, including loss of a loved one or chronic loneliness

People can develop addiction to:

  • Alcohol
  • Marijuana
  • Cocaine, methamphetamine and anxiolytics
  • LSD and other hallucinogens
  • Inhalants, such as paint thinners and glue
  • Tobacco
  • Opioid painkillers, such as codeine and oxycodone, heroin

What are the effects of substance abuse on our health?

There are two components: physical and neurological effects.

  1. Physical effects include:
  • Organ damage
  • Hormonal imbalance
  • Cancer (caused by nicotine or steroid use)
  • Prenatal and fertility issues
  • Gastrointestinal disease
  1. Neurological and emotional effects include the following mental health conditions:
  • Depression
  • Anxiety
  • Memory loss
  • Aggression
  • Mood swings
  • Psychosis

How can these patients be treated?

The first step toward recovery from any substance abuse is acknowledging the problem and accepting it. Although it may seem like a hopeless situation, change is possible with the right treatment and support.

Successful treatment has several steps:

  • detoxification (the process by which the body clears itself of a drug)
  • behavioral counseling
  • medication (for opioid, tobacco, or alcohol addiction)
  • evaluation and treatment for co-occurring mental health issues such as depression and anxiety
  • long-term follow-up to prevent relapse


Most importantly, don’t forget that every little effort counts and it will soon make a difference.
“I’ve been clean for seven years but still think about using heroin every day. Sometimes the thought is fleeting, but sometimes it scares me how long I think about using it. Whenever it gets to be too much, I also think about the hopelessness of that time in my life. Recovery can be a struggle, but it’s a struggle that gives me my life today.”

– Jim, executive marketing professional

COPYRIGHT: This article is property of We Speak Science, a non profit institution co-fonded by Dr. Detina Zalli (Harvard University) and Dr. Detina Zalli (Imperial College London). The article is written Inva Mamica (University of Medicine, Tirana).