Although everyone experiences anxiety to some degree, for some people anxious feelings are all too familiar and intense, and pose a significant barrier to leading a normal life. Those who suffer in this way are said to have one form or another of ‘anxiety disorder’. Precise definitions in regard to this disorder are sometimes difficult to determine, given the normality of a certain amount of anxiety in everyone’s lives, and the way that anxiety disorders sometimes blend together with other psychological problems. Different types of anxiety disorders are examined and their causes. In concluding the paper treatment options are discussed.