Excessive worry and apprehension are associated with general anxiety disorders. Individuals may experience restlessness, irritability, problems in concentration, muscular tension, and problems sleeping. Excessive worry about a variety of aspects of life is common, with anxiety being diffuse rather than related to a specific fear (phobia), rituals or obsessions (obsessive-compulsive disorder), or physical complaints (somatoform disorder). These disorders have been characterized as neuroses, as they all are associated with anxiety of one type or another. The term neurosis is a broad one and, because of its general nature, is used infrequently most frequently by early theorists such as Freud, Jung, and Adler. In general, the term anxiety disorder can be said to include nonspecific neuroses or anxiety.