I think a bad conscience is the root cause of alcoholism. He may say it was stress that drove him to drink. She may say it was grief and loneliness that drove her to drink. Of course, alcohol and drugs are not the only escapes from guilt. Some people talk, talk incessantly, compulsively, and never listen quietly, lest they hear something they don't want to hear.
Some people devote themselves day and night to games and hobbies and sports.
But the oldest and most revered tactic for avoiding the misery of guilt is religion. This tactic may be the most deceptive because it comes closest to the truth. The means that religion has developed to deal with this guilt is to try to placate or appease God with good works or religious ritual. Religious people know they owe God a great debt for their disobedience. But they often make the terrible mistake of thinking they can pay it back through good works and the performance of religious duties.