How Drug Abuse can Affect the Brain and Behaviour

Any addiction is of serious concern. No one begins to take drugs or drink too much with the intention of becoming addicted, with the intention of developing serious health problems.  But prolonged drug or alcohol use can have a serious impact upon a person’s health, both physical and psychologically.  Addiction can undermine and even destroy relationships and families. It can destroy careers and have a substantial impact upon a person’s financial health.  If a person becomes addicted to drugs and alcohol, then drug and addiction counselling is often required.  

An addiction is an uncontrollable, strong need for a certain substance or behave, such as to take drugs, drink alcohol, to gamble. The person will seek out drugs, even though they know the harm they can cause.  When a person takes drugs or drinks for the first time, it is usually through their choice.  But with repeated drug or alcohol use, the substance can start to have negative effects. It can become the most important thing in a person’s life. More important than their family, their job or their life.  It can also lead to problems at home, at work and in education.  It can cause the person to search out drugs or alcohol and use them again and again.  The impact on the person’s life and behaviour will really depend on the severity of their addiction.

People may not always realise that they are addicted.  They may think they can control what they are doing.  The National Institute for Drug Abuse in America suggests that if a person answers yes to any of these questions, they require professional help.

  1. Have you ever ridden in a car driven by someone (including yourself) who had been using alcohol or drugs?
  2. Do you ever use alcohol or drugs to relax, to feel better about yourself, or to fit in?
  3. Do you ever use alcohol or drugs when you are alone?
  4. Do you ever forget things you did while using alcohol or drugs?
  5. Do family or friends ever tell you to cut down on your use of alcohol or drugs?
  6. Have you ever gotten into trouble while you were using alcohol or drugs?”

There are many potential treatments to help people with addiction, but you should firstunderstand the impact of drugs on the brain.


Drugs and the Brain

Drugs are chemicals.  They affect the brain’s communication systems and affect how our nerve cells send, receive and process information. The exact impact on our brain will vary between different drugs and alcohol as they all work differently. But there are two main ways in which they act on our brain –

  • They imitate the brain’s natural chemical messengers
  • They overstimulate the reward circuit within the brain.

For example, heroin and marijuana have chemical structures that effectively mimic neurotransmitters that occur in our body.  They trick our receptors and activate nerve cells, but they don’t work in the same way as natural neurotransmitters. This means that the neurons end up sending abnormal messages around the brain, which causes problems for the brain and our bodies.

Other drugs, such as methamphetamine and cocaine can cause the neurons to release too much dopamine or to prevent the normal recycling of dopamine. Dopamine is a natural neurotransmitter.   This has the effect of exaggerated messages passing around the brain which causes problems with the communication channel. A way to imagine this is that it can create a difference between someone whispering compared to shouting into a microphone.  

Many drugs, such as cocaine, marijuana and nicotine, affect the brain’s reward circuit. This is part of the limbic system.  When the reward circuit feels pleasure, it normally responds by releasing dopamine, as this creates feelings of pleasure. When a person takes drug, it can cause high levels of dopamine into the brain, which causes a “high” or intense euphoria that can be linked to drug abuse.

Our brains are made developed to make sure we repeat healthy activities by making us feel good. For example, we might feel good after eating.  The reward circuit will react and think that something important has happened that needs to be repeated without us having to think about it.  Drugs and other pleasurable activities can do the same.  For example, regularly drinking alcohol, taking drugs, smoking, gambling, using the internet (such as porn sites), shopping and sex can lead to pleasurable feelings, which can lead to a strong desire to repeat them more often.

They can make the brain think that because it felt good when taking drugs, that it should repeat that . The brain doesn’t distinguish because a natural healthy “good feeling” and the negative, fake “good feeling” that drugs create.  So when a person repeatedly uses a drug, the brain will start to adjust to the dopamine increases.  The brain will start to reduce the levels of dopamine. Due to the toxicity of some drugs, some neurons may also die. This results in the person feeling reduced pleasure – depressed, lifeless and so on. They may not enjoy things that once brought them pleasure. So the person starts to need the drug more to bring their dopamine levels to normal. And then they need more and more to create the “high”. This is known as tolerance.

In the long term, drugs can lead to dramatic changes in the brain circuitry and neurons, even if a person has stopped taking drugs.