Addiction: From Drugs to Brain to Behavior

Addiction is a very common concept in today’s society. When we think about addiction, we usually picture drug addicts, looking for another fix. Addiction, however, can take up many different forms and shapes. It can appear and develop for a variety of reasons. Of course, drug addiction is one of the big points. There are so many different psychoactive substances in the world. Despite that fact, there are certain activities that people can engage in that can cause addiction. These activities can range from gambling to shopping, to sex. Obviously, when we have a drug addiction, we have a physiological and biological consequence that happens as a result of prolonged use of the substance. Nonetheless, we also have a psychological addiction that can play a big role.


What is an Addiction?

The difference between psychological and physiological types of addictions are quite important due to different approaches to treatment. There is a variety of different reasons why people become addicted. When we hear about addiction it often seems like such a faraway concept, however, more and more people in today’s society become addicted to something. Addiction has a high comorbidity with mental disorders, situational factors like stress and there are also some neurological underpinnings that can play a role. The feeling of pleasure that people get from doing drugs is not the sole reason why they choose to do them. We all know that methamphetamine is bad for us, yet there are so many people around us who are addicted to it. Let’s not talk even talk about methamphetamine.

Nicotine, tobacco is so widespread nowadays that nobody bats an eye at somebody who pulls out a cigarette. Cigarettes are drugs, however. They contain psychoactive substances that alter our mind and they definitely cause addiction. Same with alcohol. Yet they are such big concepts of our everyday life. It’s important to understand these intricate variations between different types of addictions in order to be able to prevent it, identify it and treat it as soon as possible.

We consider addiction to be a brain disease. A condition, that makes a person seek out an activity or a certain substance. This activity or substance may seem to bring pleasure. With continuous use and engagement, however, it starts becoming dangerous due to its constant interruption of everyday life. Addiction disrupts normal functioning and may endanger social relationships, work life and cause individual health problems.

People don’t think they will become addicted when they first use a substance or engage in a pleasurable activity. Do you ever think your shopping sprees will become detrimental to your health? I didn’t think so. Because of that, it is quite wrong to think of those who suffer from addiction, as immoral or people who cannot lead a normal life. Addiction can spring upon anybody, a lot of times without people even knowing it’s happened.

Types of Addiction

Drug addiction

The most well-known type of addiction is, of course, drug addiction. People use psychoactive substances and these psychoactive substances affect and alter the status of these people. Different psychoactive substances produce different effects on people. Scientists found that some people are a lot more likely to develop an addiction to certain substances more than to others. In order to understand the process of drug addiction, it’s important to look at different types of substances that you can get addicted to. People develop an addiction to prescribed drugs, as well as those that are illegal. Overall, we can recognize three different types of drugs:

  • Depressants: these substances decrease and reduce the activity in the brain and the central nervous systems. These drugs are known as downers due to the fact that they bring relaxation and a state of euphoria. One of the most known depressants is alcohol. People tend to think that alcohol is a stimulant, however, it reduces reaction speed and attention skills. Other depressants include opiates. We know them by their other names like morphine and heroin. Some prescribed drugs like benzodiazepines and barbiturates that are used in the treatment of anxiety are depressants as well.
  • Stimulants: these types of drugs increase central nervous system activity, therefore, the name – stimulants. They can make you more alert and focused and give you energy. I would imagine that you can think of one of the most abused drugs in history that is a stimulant. Or can’t you? Well, let me help you out. Caffeine. Every coffee cup that you drink in the morning is a shot of stimulation into your brain and into your nervous system. Other known stimulants include ecstasy or MDMA, cocaine, and crack-cocaine, methamphetamine, energy drinks, drugs for attention-deficit (Adderall, Ritalin, Concerta etc.), nicotine.
  • Hallucinogens: these substances caused an altered state of mind and consciousness. They are able to chan
    ge emotion and perceptual awareness and your thinking. They have a huge effect on your senses and can cause you to see, smell, hear and taste things that aren’t actually there. Hallucinogens tend to affect and enhance the mood of the person. Some known hallucinogens are LSD, peyote and magic mushrooms.

Drugs and the brain: how do they work?

Drugs happen to be chemical substances and they are able to affect the brain in various ways. They usually do so by interfering with how neurons communicate with one another. They can either enhance or diminish the sending, receiving and processing information functions. In the normal functioning after the neuron sends the information onto the next neuron and the neurotransmitters or chemical messengers are not needed anymore, they are re-uptaked back or ‘cleaned’ up. Some drugs will block this re-uptake, therefore, leaving an enormous amount of these neurotransmitters in the synaptic cleft which causes the message to be enhanced and disrupts further communication. Amphetamine and cocaine do that.

Other drugs like heroin and marijuana are able to mimic a neurotransmitter by attaching themselves to the post-synaptic receptors. Therefore, they can activate other neurons but not in the same way as a neurotransmitter would. Because of that, they will send different messages along the pathways of the network, therefore, altering its normal functioning.

 Drugs and the brain: why do we become addicted?

The reason why people get addicted to drugs so easily is due to the state of euphoria and pleasure that they bring us. That momentary escape from reality and your daily problems can become quite the relief for a lot of people. Drugs are able to affect the reward system in the brain by affecting one of the most important chemical messengers responsible for pleasure – dopamine. Dopamine is responsible for emotion, pleasurable feelings and motivation. Dopamine is the neurotransmitter that pats us on the back and tells us we did a good job after we get an ‘A’ on the test. That happens naturally, during a normal course of a lifetime. When we stimulate dopamine directly, we experience that sense of highly enhanced euphoria. We like it. We want to repeat it.

Dopamine and reward

During the natural course of life, we tend to repeat things that are pleasurable to us. We do so because our brain associates these activities with pleasure and reward. The brain remembers the activity and tells us that we should repeat doing the activity without a second thought. Psychoactive substances are actually able to give better activation of the reward circuit and bigger pleasure – so our brain remembers that. And tells us to repeat it. In fact, some drugs are able to release more dopamine than sex and they do so very fast. Due to the make-up of these substances and how they are taken, they are able to be absorbed into the bloodstream at a very fast rate.

If you think about it, certain drugs can be taken intravenously so they go into your bloodstream immediately and you immediately feel the effect. Smoking produces similar results, it is obviously slower than an injection. Despite that, due to the large absorption area in our lungs and a rich blood supply nearby, the drug (e.g nicotine), is able to go into the brain very fast. Other drugs are very lipidic and fatty so they are able to pass through the blood brain barrier and, ultimately, affect the nervous system. In the end, our brain receives a much higher input of pleasure which is a good motivation for people to repeat the experience.


When people use drugs continuously for a very long period of time their brain becomes used to this much amount of dopamine. The brain will start to compensate by naturally either making a smaller amount of dopamine and decreasing the receptors where dopamine binds in an attempt to regulate things back into homeostasis. Dopamine will therefore not be able to produce as much pleasure anymore, for any activities. That’s why it’s so difficult for a person who abuses drugs to get back into normal life – the pleasure they used to feel from regular activities diminishes.

They become victims of a vicious cycle where they have to keep consuming the substance in order to fill the dopamine hole and at least get it back to normal amounts. Since the person has been taking the drug for a while, he will have to start taking more and more and more in order to reach the same level of pleasure. The drug will not produce the same euphoria anymore and in an attempt to repeat it, people will increase the dosage. We know this concept as tolerance.

Behavioral Addiction


Apart from drug addiction, people also tend to engage in certain activities that become addictive. For some these activities will disrupt their normal way of functioning and activate the reward circuits in similar ways that drugs do.

Types of addictive behaviors

  • Working
  • Internet
  • Sex
  • Pornography
  • Food
  • Shopping
  • Exercising
  • Video games

Impulse Control Disorders

Certain disorders can fall under the umbrella of addiction. These disorders are characterized by impulses that people cannot control.

  • Pyromania (setting things on fire)
  • Gambling
  • Intermittent explosive disorder (acts of aggression)
  • Kleptomania (stealing)

Addiction Symptoms

Different types of addictions display different types of symptoms and warning signs. It’s important to know them in order to be able to identify them as soon as possible on your loved ones and yourself. Identifying the symptoms as soon as possible helps in getting the best possible treatment. It also gives the best prognosis for the outcome.

Drug addiction symptoms

  • Not being responsible for obligations.
  • Putting in effort in order to obtain the drug
  • Needing more of the drug in order to feel the effect
  • Feeling that you need the drug
  • Having a feeling that you should use it on a regular basis
  • Engaging in activities that are not normal to you in order to obtain the drug
  • Spending all of your money on the drug
  • Failing when you try to stop using the drug
  • Feeling withdrawal symptoms when you try to stop using the drug
  • Not engaging in social activities that you used to enjoy

Some warning signs include:

  • Behavioral changes
  • Spending a lot of money
  • School/work issues
  • Personal hygiene problems
  • Problems with health

Behavioral addiction symptoms

  • Workaholics: we live in a society that rewards people who work overtime and work hard. Due to this, it becomes a bit difficult to recognize somebody whose obsession with work has become unhealthy. Workaholics will feel a strong sense and need of control of themselves and those around them. They will usually try to do all the work themselves. They will not notice the effect over-working has on their physical and emotional welfare. These people set standards that are really high and not reaching them makes them feel like failures. People who have work addiction will not spend a lot of time on their personal relationships, putting all of their efforts into work. They will engage in work activities in order to forget about all the other problems.
  • Shopping: quite a famous concept is the addiction to shopping or as people would say, somebody who is a shopaholic. They will be spending the money they cannot afford and feel a sense of euphoria when engaging in shopping activity. This can cause a lot of problems with family and social relationships.
  • Internet addicts: these people will start lying regarding what they do online. They will use the internet constantly and think about being online at all times. These people will also not be able to control how much time they spend online and the way they act online. The constant use of the internet will put their real life experiences and relationships at risk. They will not be able to stop using the internet even when they try and will experience withdrawal symptoms similar to those we see with drug use. These people will forget about their lives when they are online, without realizing how much time they’ve spent online.
  • Sex: there are some sexual disorders that seem excessive when it comes to impulses and urges that a person may experience. These compulsive behaviors may show the presence of addictive behaviors. These urges might compel people to engage in sexual activity that is unsafe for them, a variety of different partners, prostitute themselves, be addicted to pornography etc. These people will feel shame in the activities they pursue.
  • Food: these people tend to find relief in eating. They will try to hide from their everyday problems with food, however, they cannot control their obsession with food. They will try to get it under control but fail and end up binging on food. They will then feel shame afterward and not want to do it again. These spouts of eating impulses can start affecting somebody’s life and their interpersonal relationships. 

Addiction causes


Addiction can happen due to a variety of reasons. Many different things might have to come together for a person to develop an addiction, no matter the type of addiction. How does it happen that some people become addicted very easily while others do not? Some people just need to play a video game once and in no time they will be spending hours on the computer, staring absentmindedly at the screen. A variety of factors plays a role in the formation of addiction. These factors can be developmental, environmental and biological.

Environmental factors

As mentioned before, stress and trauma are quite common in today’s society. The quality of life is something that plays a big role in the development of addiction. Interpersonal relationships with family and friends, intrapersonal relationship with yourself, school/work environment. All of these outside factors can influence the development of addiction. Traumatic experiences that include bullying, all types of abuse, violence can push a person into a pattern of addictive behaviors.


Nowadays, people are very likely to start using drugs very early in life. The problem is that the earlier a person starts the abusive behaviors, the harder it will be to treat. Not only because a person might spend a lot more time engaging in an activity or consuming a substance. It’s also due to the fact that young people, especially teenagers are not developed enough and are not able to make concise decisions for their best interests. Their brain isn’t developed properly yet and they lack the skills involved in decision making, critical thinking and more so judgment. That’s the reason why the younger population nowadays is very at risk of displaying these addictive symptoms.


The biological makeup of every person can make them be a lot more prone to developing an addiction. Certain genetic and neurological underpinnings and predispositions can play a role.


According to Bevilacqua and Goldman talk about twin studies done in order to discover the origins of addiction. They mention one that found a familial link between drug addiction to marijuana, nicotine and alcohol in adolescents. They mention that heritability may play a role and in combination with other environmental and situational factors can cause the development of addiction. In conclusion they say that genes by themselves might not be the sole cause of addiction, however, in a combination of factors they do provide a vulnerability to the affected population.


As mentioned before, addiction manages to activate the reward circuit in the brain and alter brain functioning, especially when it comes to the use of psychoactive substances. Many studies in particular focus on drug addiction, but it applies to other forms of addictions as well. According to Garrison and colleagues in their 2014 report via the use of a plethora of neuroimaging methods, there have been some areas identified that might become biomarkers for the development of addiction. Different aspects that relate to addiction that include craving and relapse are especially linked with these areas. According to them, there is activation in the orbitofrontal cortex, ventral striatum, insula and the amygdala. This activity may show a disturbance in information processing.

Neurotransmitters and brain areas

Parvez and colleagues in 2011, mention dopamine once again and talk about the reward network that activates as a result of the addiction. Apart from dopamine, addiction and, specifically, drug addiction seems to have an effect on other neurotransmitters as well, including GABA, glutamate, and others. Again, they note the importance of some areas including the striatum, orbitofrontal cortex and the prefrontal cortex in relation to the use of cocaine. These areas have a link also with bingeing behaviors which could prove to be crucial in the development of food addictions, specifically the orbitofrontal cortex.

Fowler and others in 2007 study talk about dopamine once again and mention that the original levels of dopamine in the brain might be a risk factor for the further development of addiction. They mention that those who might have lower levels of dopamine receptors could potentially be more vulnerable to the development of addiction.

Addiction treatment

Treatment for addiction is available but it’s not an easy or a fast method. Addiction is a disease and people cannot just quit using drugs one days and be fully treated. Long-term care needs to be provided for affected people. Also, treatment techniques need to be very individually based and identify all of the needs of the patient, not just the addiction itself. That means paying attention to possible mental disorders, due to the fact that addiction is often comorbid with other disorders including depression, anxiety disorders, phobias and personality disorders. Depending on the addiction the treatment can consist of a combination of pharmacotherapy and psychotherapy. If the addiction involves psychoactive substances, people need to be detoxified as well and be rid of the drug within their systems. They need to be treated long and continuously in order to prevent relapse back into the addiction.


Behavioral addictions treatment


Drug addiction is very serious, however, behavioral addictions should not be taken lightly either. A professional will have to think about the combination of a variety of strategies to help out the person. Cognitive behavioral therapy is used widely in the treatment of behavioral addictions. Both, group and individual sessions are quite helpful for support and reflection. Mental and physical exercise and art therapy prove to be beneficial as well. Therapy needs to be customized individually in accordance with each addiction and each personality. Clinicians attempt to prevent the possibility of relapse and provide support groups that can help the person in their long-term recovery. Sometimes, inpatient treatment is needed in order to be able to keep an eye on the person throughout the day. This can be particularly important with food obsessions and those addictions that are comorbid with other disorders.

Drug addiction treatment

A variety of treatments are available for those suffering from substance abuse. Specialized professions, support groups, both inpatient and outpatient treatments. The combination of pharmacotherapy and psychotherapy is used again. Cognitive-behavioral therapy has proven to be beneficial once again, including both individual and group support and sessions. Depending on the substance used, the medical treatment may differ.

For example, people who are addicted to depressants, specifically for opioids will be treated with drugs like naltrexone or methadone. A variety of options are available for those who are trying to quit smoking tobacco including sprays, patches, and gums. This treatment medicine seems to work in a similar way as the original drugs and attempts to slowly put the patients off of the drug. These medications in combination with behavioral therapies that work on cravings and teach people skills to integrate them back into society. Group therapy has proven to be specifically beneficial due to constant support and social interaction. Seeing others going through a similar thing can reinforce one in a very powerful way!

Addiction relapse

Often times, no matter how successful the treatment seems to be, relapse still occurs. Relapse refers to a moment when the people go back to engaging in addictive behaviors or using a substance. Sometimes these relapse episodes can be momentary with people moving back to their treatment almost immediately, other times relapse can last for quite a long time, threatening the treatment as a whole. People who go through relapse need to realize that relapse is a common occurrence. Of course, it’s very disappointing and might be considered a failure by you and others, but it is a part of recovery. Sometimes consulting with your support group, your therapist and people that are close to you, reflecting upon yourself can help get back on track. Changing certain strategies can prevent relapse from happening again. It’s important to move forward no matter how many times relapse episodes may happen.

DSM-V Changes: Addiction

Diagnostic and Statistical Manual has included the gambling disorder as a part of addictive disorders. The manual provides a variety of criteria for substance use disorders that include concepts like craving, withdrawal, intoxication. In fact, craving is a new concept. People need to experience 2 or more symptoms underlined in the criteria lists in order to be classified as a substance use disorder and will further specify how strong the disorder is by the increasing number of criteria.

Addiction Lifestyle

It is important to remember that addiction is a disease. Therefore, treatment strategies should take that into account. If you or a loved one suffer from addictive behavior or substance use, get professional individualized treatment and provide full support for the person. No matter how hard it may seem, recovery and rehabilitation is in your hands and you can make it happen!


Fowler JS, Volkow ND, Kassed CA, Chang L. Imaging the Addicted Human Brain. Sci Pract Perspect [Internet]. 2007;3(2):4–16. Available from:

Parvaz MA, Alia-Klein N, Woicik PA, Volkow ND, Goldstein RZ. Neuroimaging for drug addiction and related behaviors. Rev Neurosci. 2011;22(6):609–24.

Garrison KA, Potenza MN. Neuroimaging and Biomarkers in Addiction Treatment. Vol. 16, Current Psychiatry Reports. 2014.

Bevilacqua L, Goldman D. Genes, and addictions. Clin Pharmacol Ther [Internet]. 2009;85(4):359–61. Available from:


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