According to Elizabeth Hartney, PhD. "Although a boundary can be clearly marked by a fence or a road, it is never entirely clear exactly where one area ends and the other begins. In a similar way, when we use the word boundaries to describe limits and rules in relationships, some honest judgment is needed to decide which behaviors "cross the line."

In her article, Dr. Hartney discusses the common difficulties for boundaries and addiction, and provides principles for setting good boundaries.