The two parts of the brain most affected by the disease of addiction are the primitive brain or reptile and the neomammalian cortex or brain. These images show how scientists can use imaging technology to measure brain and heart function. Higher activity is shown in reds and yellows, and reduced activity in blues and purples. Both healthy brains and hearts are more active than sick brains and hearts, because both addiction and heart disease cause changes in function.
In drug addiction, the frontal cortex, in particular, shows less activity. It is the part of the brain associated with judgment and decision-making (NIDA). Addiction affects the brain on many levels. The chemical compounds in stimulants, nicotine, opioids, alcohol, and sedatives enter the brain and bloodstream when used.
Once a chemical enters the brain, it can cause people to lose control of their impulses or to want to consume a harmful substance. All addictive drugs affect the brain pathways and involve a reward, that is, the dopamine system in the reward pathway. The brain disease addiction model has improved the understanding and treatment of substance use disorders. One of the criticisms of the addiction model of brain diseases is that it does not reduce the moral stigma associated with addiction, but can instead add a new stigma by using the word illness.
This model takes into account the genetic and environmental factors that cause physical changes in the brain and significantly increases the basic understanding of addiction, which can lead to more accurate and effective treatment options. The American Society for Addiction Medicine (ASAM) defines addiction as a disease that affects brain chemistry and circuits, which then leads to compulsive drug-seeking and using behaviors. The brain responds to addiction based on several factors, such as the type and quantity of drugs used, the frequency of use, and the stage of addiction that has developed. Addiction specialists have found that people with active addictions experience abnormalities in the brain of reptiles.
In addition to neurobiological changes, the addiction model of brain disease also points out that many genetic, environmental and social factors contribute to a person's vulnerability to starting to use drugs, continue to use drugs and undergo the progressive changes in the brain that characterize addiction.