In a new study, researchers found the physical origin of alcohol addiction is located in a network of the human brain that regulates our response to danger.
The research was conducted by a team at the University of Warwick and elsewhere.
The medial orbitofrontal cortex (mOFC) at the front of the brain senses an unpleasant or emergency situation, and then sends this information to the dorsal periaqueductal gray (dPAG) at the brain’s core, the latter area processing whether we need to escape the situation.
In the study, the team found a person is at greater risk of developing alcohol use disorders when this information pathway is imbalanced in the following two ways:
Alcohol inhibits the dPAG (the area of the brain that processes adverse situations), so that the brain cannot respond to negative signals, or the need to escape from danger—leading a person to only feel the benefits of drinking alcohol and not its harmful side effects.
This is a possible cause of compulsive drinking.
A person with alcohol addiction will also generally have an over-excited dPAG, making them feel that they are in an adverse or unpleasant situation they wish to escape, and they will urgently turn to alcohol to do so.
This is the cause of impulsive drinking.
The research team had noticed that previous rodent models showed that the mPFC and dPAG brain areas could underlie precursors of alcohol dependence.
They then analyzed MRI brain scans from the IMAGEN dataset—a group of 2000 individuals from the UK, Germany, France and Ireland who take part in scientific research to advance knowledge of how biological, psychological and environmental factors during adolescence may influence brain development and mental health.
The participants undertook task-based functional MRI scans, and when they did not receive rewards in the tasks (which produced negative feelings of punishment), regulation between the mOFC and dPAG was inhibited more highly in participants who had exhibited alcohol abuse.
Alcohol use disorder is one of the most common and severe mental illnesses.
According to a WHO report in 2018, more than 3 million deaths every year are related to alcohol use worldwide, and harmful alcohol use contributes to 5.1% of the global burden of disease.
Understanding how alcohol addiction forms in the human brain could lead to more effective interventions to tackle the global problem of alcohol abuse.
One author of the study is Professor Jianfeng Feng.
The study is published in Science Advances.
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