The Ohio Lottery and the Ohio Department of Alcohol and Drug Addiction Services will hold a conference on problem gambling this week in central Ohio just days after the opening of the state's fourth voter-approved casino. The conference for counselors across the state will be held in Columbus on Wednesday. It will offer seminars and training from experts in the areas of prevention and treatment of all aspects of problem gambling. Ohio Lottery Director Dennis Berg says it's critical to focus on training, prevention and treatment as the state's gambling landscape expands. The $400 million Horseshoe Casino Cincinnati opens today. Two of the state's other casinos opened in May in Cleveland and Toledo. The first casino opened in Columbus in October.