title: Theories of anxiety: a theoretical perspective.
mesh_terms: D001007:Anxiety / Q000209:etiology*; D001008:Anxiety Disorders / Q000209:etiology; D003220:Conflict, Psychological; D003674:Defense Mechanisms; D003858:Dependency, Psychological; D005086:Existentialism; D005239:Fear; D006791:Hostility; D006801:Humans; D011574:Psychoanalytic Theory; D013812:Therapeutics