Addiction and Reward Circuit

Various forms of addiction

While addiction is often associated with the use of psychoactive substances (alcohol, drugs, medication, tobacco, etc.), other forms of behavioural addiction also exist:

• Gambling
• Sports activity
• Sex
• Technology (cell phones, social networks, etc.)
• Shopping (compulsive purchases, hoarding, etc.)
• Food
• Emotional addiction

The reward circuit

Addiction occurs when the reward circuit is disrupted. What is this reward circuit?

When we perform a pleasant task, the brain produces dopamine, among other effects. Dopamine is one of the molecules responsible for the sensation of pleasure, which is why it is called the “pleasure molecule.” This molecule is a neurotransmitter secreted by the body when certain actions are performed: this is the reward circuit.

The main function of this reward circuit is to promote behaviours necessary for survival: drinking, eating, reproduction, etc. For example, when a person feels hunger, eating releases dopamine and gives the brain a feeling of pleasure and reward. The pleasure derived from these activities drives a person to repeat the activity, therefore ensuring survival.

These vital functions are not the only activities that cause us to secrete dopamine. For example, it can be secreted when listening to music, playing sports or doing any of the activities mentioned above (gambling, compulsive shopping, etc.).

When the reward circuit is functioning normally, it contributes to mental well-being.

Tolerance and dose escalation

When a person regularly uses certain substances, they may develop a tolerance: the feeling of pleasure provided by the substance becomes less and less intense. The person must therefore increase the dose to achieve the level of pleasure provided by the initial doses.

This phenomenon of tolerance plays an important role in the transition to problematic use, whereby the substance occupies an increasingly central place a person’s life, often to the detriment of their health and social life. In the most severe cases, the substance may become the addicted person’s sole focus. They then spend most of their time and money acquiring and administering the substance, repeating the cycle.

Note: not all substances lead to tolerance. This is the case with amphetamines, for example. However, it is possible to become addicted to a substance without developing tolerance.

Tolerance is also a factor in behavioural addictions, including gambling. A person may feel driven to devote more and more time to gambling in order to maintain a certain level of pleasure, to the detriment of their social life and financial health.

Psychological addiction, physical addiction and withdrawal

There are two types of addiction: physical addiction and psychological addiction. These two forms of addiction are very different from each other.

Physical addiction

Physical addiction occurs when the body has become so accustomed to a substance that it requires it to function. When an addicted person stops using the substance, they experience cravings and symptoms: this is known as withdrawal.

Depending on the nature of the substance, withdrawal symptoms can vary in intensity, and may include headaches, trembling, nausea, etc. Withdrawal from certain substances, including opiates, can cause pain to the point that withdrawal becomes intolerable and requires medical assistance.

Psychological addiction

Psychological addiction stems from the effects of a substance or behaviour and the context surrounding it. It is influenced by a number of factors, including a person’s personality, lifestyle and social circle. In addition to being physically addicted, a person can also be triggered by the memory of the pleasure provided by a substance or activity. Psychological addiction lasts much longer than physical addition and can even last a lifetime.

For example, when a person smokes tobacco, nicotine quickly becomes physically addictive. After quitting smoking, this physical addiction will disappear after several days. On the other hand, psychological addiction will last longer because it is tied to habits that involve the ritual of smoking, such as coffee breaks or having a cigarette at the end of a meal. These memories continue to drive a person’s desire for cigarettes, even if they no longer suffer from any physical addiction.