Brain Physiology
Alcohol causes depression and laziness through its effects on the brain. The brain is made up of cells called neurons. The neurons in the brain control a number of things, including cognition, sensation, muscle movement, balance and emotions. Neurons throughout the brain are connected via small junctions called synapses. Neurons use these synapses to communicate with each other via neurotransmitters, which are chemicals that neurons make and secrete. When one neuron gets stimulated, it releases neurotransmitters into the synapse. These neurotransmitters then can either stimulate other neurons in the synapse, generating a nerve signal, or they can inhibit other neurons, making them less active.
Alcohol and Neurotransmitters
Alcohol is able to easily cross into the brain and affect the neurons there. According to the ChemCases website, the overall effect of alcohol is to inhibit neuron activity in the brain. It does this in a few different ways. One mechanism by which alcohol lowers brain activity is by increasing the turnover of two stimulatory neurotransmitters, norepinephrine and dopamine. By causing these neurotransmitters to be in synapses for less time, it decreases their ability to stimulate neurons. Alcohol also inhibits the action of another kind of stimulatory neurotransmitter called acetylcholine. Finally, alcohol increases the signalling of the neurotransmitter GABA, which is responsible for blocking neuron activity. As a result, alcohol works throughout the entire brain to depress neuron activation. One effect of blocking neuron activity is that there is less stimulation of the mood portions of the brain (also known as the amygdala). Decreased stimulation of these neurons leads to depression.
Alcohol and Endorphins
Neuroscience For Kids notes that alcohol use also causes increased production of a certain neurotransmitter called endorphins. Endorphins are released in a part of the brain called the hypothalamus, which is responsible for perceiving pleasure. Because alcohol causes there to be more endorphins in the hypothalamus, this leads to the brain associating alcohol with pleasure. Because alcohol use gives the brain a chemical reward, it causes people to associate the consumption of alcohol as a positive event. This makes people who regularly use alcohol less likely to engage in other activities because they feel pleasure in drinking alcohol. This endorphin release, coupled with the overall decreased brain activity, causes people to become lazy if they regularly drink alcohol.
