Alcohols Affect on the Brain

Consumption of alcohol is often a large part of students’ college experience and plays into their sexual behavior too. Known to cause behavioral changes and increase risky behavior, alcohol is a large risk factor for increased dangerous sexual decisions and can place students in vulnerable positions. Looking more specifically at the biological affect of alcohol on the brain reveals just how much of an effect alcohol has on the body and on behavior.

Alcohol is distributed throughout the body through water and so has primary effects on water-containing organs, the largest two being the liver and the brain. Alcohol interacts with many systems in the brain, sometimes stimulation neurotransmission and sometimes inhibiting it, but primarily affects the brain by acting with the reward pathway in the limbic system (a network of neurons in the middle of the brain). After the consumption of alcohol, the neurotransmitter dopamine is released by a group of neurons in the ventral tegemental area, which is near the top of the brainstem. This message is relayed to the nucleus accumbens (a structure that is part of the limbic system) as well as to a related part of the prefrontal cortex, thus resulting in a pleasurable sensation.

Considering that the brain is the origin of behavior, alcohols interaction with these brain functions can lead to many behavioral changes. Alcohol can affect the cerebellum (responsible for movement), the hippocampus (responsible for memory), the ventral tegmental area (the reward system), and the brainstem (responsible for breathing). Alcohol affect on each of these systems is tied to a dose-relationship response, meaning that the higher the dose of alcohol consumed, the larger the affects.

Looking more closely at this dose-response relationship reveals the behavioral changes that can be expected at each BAC (blood alcohol concentration) level. At very low levels (BAC = 0.01–0.05) people often feel relaxed, a sense of wellbeing, and a loss of inhibition all caused by affects in the cerebral cortex and the forebrain. This leads to impaired alertness and judgment, meaning that even at minimal doses of alcohol a disposition to risky behavior arises. At BAC levels between 0.06 and 0.10 feelings of pleasure, numbness, nausea, sleepiness, and emotional arousal arise. When BAC reaches 0.11–0.20 one can expect to experience mood swings, anger, sadness, and mania, caused by the cerebral cortex, the forebrain and the cerebellum. At this time people often show decreased reasoning ability and inappropriate social behavior. As BAC rises these effects become more severe and can result in coma or death.

In terms of risky behavior, these various affects on the brain can affect the perception of risk, risk taking, acting on impulse, and sensation-seeking behavior (also as it applies to sexual behavior). This is why those who have consumed alcohol, even in small doses, have a higher disposition to the pleasures of sexual activity as well as a decreased consideration of associated risks. The consequences of such can result in rape, transmission of disease, and unwanted pregnancies.

When understanding alcohol’s affect on the brain as it pertains to sexual behavior, it is clear that alcohols direct interaction with the brain’s reward system has much to do with the witnessed increase of risky and dangerous sexual behavior. Considering the large volumes of alcohol consumed on college campuses and by college students it is important to be aware of these effects and understand the importance of safe drinking.


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