Phobia- fear and avoidance of objects or situations that don"t present any real danger. Panic disorder- recurrent panic attacks (dizziness, rapid heart rate, trembling, terror and feelings of impending doom; sometimes accompanied by agoraphobia (fear of being in public places) Generalized anxiety disorder- persistent uncontrollable worry, often about minor things. Post-traumatic stress disorder (ptsd)- aftermath of a traumatic experience (experiences arousal, avoidance of stimuli associated with the event, and anxiety recalling the event) Acute stress disorder- same symptoms as ptsd but only lasts for 4 weeks or less. Comorbidity among anxiety disorders arises for 2 reasons: Symptoms of the various anxiety disorders are not entirely disorder specific (perspiration, fast heart rate are among the diagnostic criteria for panic disorder, phobias, and ptsd) Etiological factors that give rise to various anxiety disorders are probably applicable to more than 1 disorder. As a group, anxiety disorders are the most common psychological disorders. More common in women than men across all age groups.