Many addicts inherit a brain that has trouble saying no to drugs. A study published in Science reveals that cocaine addicts have abnormalities in areas of the brain involved in self-control. And these abnormalities seem to predate any drug abuse. These images show how scientists can use imaging technology to measure brain and heart function.
The highest activity is shown in the reds and yellows, and the reduced activity is shown in the blue and purple ones. Both the healthy brain and the healthy heart show greater activity than the diseased brain and heart, because both addiction and heart disease cause changes in function. In drug addiction, the frontal cortex, in particular, shows less activity. This is the part of the brain associated with judgment and decision-making (NIDA).
Imaging studies have revealed neurochemical and functional changes in the brain of subjects addicted to drugs that provide new insights into the mechanisms underlying addiction. Neurochemical studies have shown that large and rapid increases in dopamine are associated with the reinforcing effects of drugs of abuse, but also that after chronic drug abuse and during withdrawal, brain dopamine function decreases markedly and these decreases are associated with prefrontal dysfunction regions (including orbitofrontal cortex and cingulate gyrus). Changes in brain dopamine function are likely to result in decreased sensitivity to natural enhancers, since dopamine also mediates the reinforcing effects of natural enhancers and in altering frontal cortical functions, such as inhibitory control and attribution of prominence. Functional imaging studies have shown that during drug poisoning, or during desire, these frontal regions are activated as part of a complex pattern that includes brain circuits involved with reward (nucleus accumbens), motivation (orbitofrontal cortex), memory (amygdala and hippocampus), and control ( prefrontal cortex and cingulate gyrus).
Here, we integrate these findings and propose a model that attempts to explain the loss of control and compulsive drug intake that characterize addiction. Specifically, we propose that in drug addiction the value of drugs and drug-related stimuli be increased at the expense of other reinforcers. This is a consequence of conditioned learning and the re-establishment of reward thresholds as an adaptation to high levels of stimulation induced by drugs of abuse. In this model, during exposure to the drug or drug-related signals, the recall of the expected reward results in an overactivation of the reward and motivation circuits, while activity in the cognitive control circuit decreases.
This contributes to the inability to inhibit the urge to seek and consume the drug and results in a compulsive intake of the drug. This model has implications for therapy, as it suggests a multi-pronged approach that targets strategies to decrease the rewarding properties of drugs, improve the rewarding properties of alternative reinforcers, interfere with conditioned learned associations, and strengthen cognitive control in the drug addiction treatment. When someone develops an addiction, the brain craves the reward of the substance. This is due to the intense stimulation of the brain's reward system.
In response, many users continue to use the substance; this can lead to a series of euphoric feelings and strange behavioral traits. Long-term addiction can have serious consequences, such as brain damage, and can even result in death. At this stage, the individual may not have a total addiction; however, they may have developed tolerance or dependence. Relatively new imaging technologies, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), have provided new ways to investigate how biological factors integrate with each other, how they relate to behavior, and how biological and environmental variables interact in the drug.
addiction (Figure 1) The relevance of learning and memory for addiction is evident by the pernicious effect that a place, a person or a sign that brings back memories of the drug may have on the addict who is trying to stay clean. When Alcoholics Anonymous was gaining acceptance in the 1980s, scientists in the field of addiction found that funding agencies were unwilling to support and fund research into abstinent model treatments. Not everyone with genetic vulnerability will become addicted, but when vulnerability is present, they are much more likely to fall into repeated drug use. Just as cardiovascular diseases damage the heart and change its functioning, addiction changes the brain and impairs its functioning.
Adolescents are especially vulnerable to possible addiction because their brains are not yet fully developed, especially the frontal regions that help control impulses and assess risk. Mindfulness meditation and magnetic brain stimulation are being evaluated for their ability to strengthen brain circuits that have been damaged by addiction. But even for those who have successfully quit smoking, there is always a risk of addiction returning, which is called relapse. Therefore, information from imaging studies on specific protein abnormalities in the brain of subjects addicted to drugs (e.g.
They can discover how to improve brain activity, reducing the effects of addiction and unhealthy impulses. Attempts to understand and treat addiction as a purely biological or environmental problem have not been very successful. . .