The present invention relates generally to the fields of treating psychiatric disorders, in particular, anxiety disorders including post-traumatic stress disorder (PTSD) in subjects, e.g., human subjects, by administering a xenon and/or argon containing composition. Treatments can also employ psychotherapy in combination with administration of xenon and/or argon, alone or in combination with additional psychotherapeutic medications to treat the anxiety disorder and reduce a symptom of the anxiety disorder in the subject.