The effects of alcohol in the brain:

Alcohol affects the brain's function by interacting with several neurotransmitter systems, this disrupts the balance excitatory and inhibitory neutotransmittors. 

Alcohol can affect the emotion side of the brain therefore acting like a depressant by increasing the inhibitory neurotransmission, by decreasing the exciatory neuro transmission or by a mixture of both. 

The consumption of alcohol is often accompanied by alterations in the memory, decreased attention/short attention-span, mood changes and more commonly drowsiness. 

After drinking alcohol for a long period of time, different affects start to show, these include: lethargy, confusion, amnesia, loss of sensation, difficulty breathing and death. Alcohols excitatory actions appear to be caused by supression of the inhibitory neutotransmitter systems.