An addiction is a chronic brain disease characterized by compulsive and persistent engagement in a substance or behavior despite significant negative consequences. It involves changes in brain chemistry and reward pathways, causing a surge of Dopamine. Addictive substances or behaviors cause a rapid and intense flood of the neurotransmitter dopamine into the reward circuit, producing a powerful feeling of euphoria that leads to Loss of control or Difficulty resisting the urge to use the substance or engage in the behavior. Since addictions are a complex condition influenced by a combination of biological, psychological, and environmental factors, there is not a single cause. For many, it begins with voluntary substance use or behavior. Still, it can lead to compulsive use due to significant changes in brain function, causing a person to crave, which is an Intense desire for the substance or behavior, even when it causes harm.
People eventually build up a Tolerance with repeated exposure, and the brain adapts by reducing the number of dopamine receptors. This leads to tolerance, where the individual needs to use more of the substance or engage in the behavior more frequently to achieve the same initial high, and the Need for the substance or behavior increases the amount required to achieve the same effect. As tolerance builds, the reward circuit becomes less sensitive to natural pleasures, such as food or relationships. The drive to use the substance shifts from seeking pleasure to simply feeling normal or avoiding withdrawal symptoms, leading to compulsive use, which can lead to Withdrawal or Physical or psychological symptoms when the person stops, since Addictions can affect a wide range of substances and behaviors, including drugs, alcohol, gambling, shopping, and sex. Addiction causes long-lasting changes in other brain systems as well, including those involved in judgment, learning, memory, and impulse control. These changes interfere with the ability to resist intense urges and make it difficult to quit, also making it a complex condition that can have serious consequences for individuals, families, and society.