People use alcohol sometimes as a coping mechanism. So, alcohol-dependent is a good term. Some can drink and not be affected with more than a hangover. Some can drink once and become addicted for life. I've known both types.
Then you have the happy drunk and the sullen drunk. The drunk who beats his family and the one who just sits and passes out. So many ways to go. One problem is money. It takes a lot of cash for alcohol.