Biological causes may include obsessive compulsive disorder, Postural Orthostatic Tachycardia Syndrome, post traumatic stress disorder, hypoglycemia, hyperthyroidism, Wilson's disease, mitral valve prolapse, pheochromocytoma, and inner ear disturbances (labyrinthitis). Dysregulation of the norepinephrine system in the locus ceruleus, an area of the brain stem, has been linked to panic attacks.
^ Leicht, Gregor; Mulert, Christoph; Eser, Daniela; Sämann, Philipp G.; Ertl, Matthias; Laenger, Anna; Karch, Susanne; Pogarell, Oliver; Meindl, Thomas; Czisch, Michael; Rupprecht, Rainer (2013). "Benzodiazepines Counteract Rostral Anterior Cingulate Cortex Activation Induced by Cholecystokinin-Tetrapeptide in Humans". Biological Psychiatry. 73 (4): 337–44. doi:10.1016/j.biopsych.2012.09.004. PMID 23059050.
Panic attacks can occur due to number of disorders including panic disorder, social anxiety disorder, post traumatic stress disorder, drug use disorder, depression, and medical problems. They can either be triggered or occur unexpectedly. Smoking, caffeine, and psychological stress increase the risk of having a panic attack. Before diagnosis, conditions that produce similar symptoms should be ruled out, such as hyperthyroidism, hyperparathyroidism, heart disease, lung disease, and drug use.
People with panic disorder often worry about when the next attack will happen and actively try to prevent future attacks by avoiding places, situations, or behaviors they associate with panic attacks. Worry about panic attacks, and the effort spent trying to avoid attacks, cause significant problems in various areas of the person’s life, including the development of agoraphobia (see below).