Owning Mahowny (2003) on Netflix

Based on the true story of a Toronto bank manager, Dan Mahowny is addicted to gambling. Horses and sports are only a few of his interests. Eventually, he creates dummy accounts at his bank and uses that money to fly to Atlantic City to gamble. He seems to get little joy from winning and his addiction is such that he is unable to stop in any event. Even if he wins huge amounts - which he does - he simply continues to play until he has lost it all. It's a frighteningly lonely experience that cannot include friends or anyone else around him. In the end, his hours and hours at the tables give him nothing and as his embezzlement catches up to him, he is arrested and sent to jail.