Drug abuse negatively changes how friends interact with each other. For example, a person who begins experimenting with drugs often stops associating with non-using friends. One other complication is that most users typically forget when they behave poorly toward others, says Patricia O'Gorman, a psychologist and substance abuse specialist interviewed for "Teen Vogue" magazine. However, the disorientation that drug users experience also allows them to deny angry comments or extreme mood swings, which poses additional challenges for non-users who want to maintain the friendship.