...are deeply unhappy people?
What I'm NOT saying is that "these people are unhappy, therefore they drink".
(Though it may be true initially in many cases)
That gets it backwards.
Think about it. People who get drunk all the time are regularly messing with their brain chemistry - serotonin, cortisol, etc, and stimulating the sympathetic nervous system and the adrenal glands.
Over time, this will F*CK UP your brain's natural methods of regulating mood and happiness.
Druggies are incredibly depressed people. It also follows that people who get drunk all the time are lowering their overall happiness. Find a drunk when he's sober, tell me if he's a happy person.
The brain is a physical organ. Poisoning it on a weekly basis to loosen up is going to have serious repercussions.