Alcohol is often thought of as a stimulant because of the euphoric feeling a person feels after one or two drinks. However, nothing could be further from the truth. In fact, alcohol is a powerful depressant that causes chemical changes in the central nervous system and the brain. There is a direct relationship not only between alcohol and mood swings, but also between alcohol and anxiety, depression, memory, concentration, and judgment.
The human brain is made up of approximately one trillion nerve cells known as neurons. Neurons communicate with each other through electrical and chemical neurotransmitters, allowing messages to be sent throughout the body. The messages serve to maintain cognition, heartbeat, lung function, mood, and many other processes. The relationship between alcohol and mood swings comes into play if the transmission of these critical signals is slowed down, blocked, or interrupted. Alcohol hampers the ability of neurons to drive body systems at the correct speed, and negatively affects an individual's cerebellum, cerebral cortex, and limbic system.
The latter two areas largely regulate memory, emotion, behavior, judgment, and recognition of social cues. Alcohol's role in mood swings is the result of a direct cause-and-effect scenario in which the intoxicating substance slows down or stops messages to the necessary parts of the brain. Drinking too much alcohol not only makes you forget names, dates or figures, it also makes your cerebral cortex and limbic system forget how to react and behave. This loss of cognitive ability and emotional control can be temporary, but in the case of long-term alcohol abuse, it can sometimes be permanent.
A link between alcohol and mood swings is further exemplified by liquor's influence on endorphins and serotonin. The former is a substance in the brain that aids in relaxation, and the latter is a neurotransmitter that plays an important role in controlling emotional peaks and troughs. The interruption of neurotransmissions caused by alcohol forces the brain to function without feedback from all its parts. It attempts to compensate for this "blind" state by sending out a signal that releases excessive amounts of serotonin and endorphins. This massive release confuses the body and mind, causing a person under the influence of alcohol to sometimes appear ecstatic one instant and violently angry the next.
Researchers believe that the connection between alcohol and mood swings depends in part on how often you drink. The amount of alcohol consumed regularly is another factor, as is one's genetic makeup. Alcoholism and alcohol intolerance are inherited traits, and if the abuse is identified early, some of the damage inflicted on the brain can often be reversed.