The parvocellular neurosecretory neurons of the hypothalamus release corticotropin-releasing hormone (CRH), which is sent to the anterior pituitary. Here the pituitary releases adrenocorticotropic hormone (ACTH), which ultimately stimulates the release of cortisol. In relation to anxiety, the amygdala activates this circuit, while the hippocampus is responsible for suppressing it. Glucocorticoid receptors in the hippocampus monitor the amount of cortisol in the system and through negative feedback can tell the hypothalamus to stop releasing CRH.Studies on mice engineered to have high concentrations of CRH showed higher levels of anxiety, while those engineered to have no or low amounts of CRH receptors were less anxious. In people with phobias, therefore, high amounts of cortisol may be present, or there may be low levels of glucocorticoid receptors or even serotonin (5-HT). Disruption by damage
For the areas in the brain involved in emotion—most specifically fear— the processing and response to emotional stimuli can be altered when one of these regions is damaged. Damage to the cortical areas involved in the limbic system, such as the cingulate cortex or frontal lobes, has resulted in extreme emotion changes. Other types of damage include Klüver–Bucy syndrome and Urbach–Wiethe disease. In Klüver–Bucy syndrome, a temporal lobectomy, or removal of the temporal lobes, results in changes involving fear and aggression. Specifically, the removal of these lobes results in decreased fear, confirming its role in fear recognition and response. Damage to both side (Bilateral damage) of the medial temporal lobes is known as Urbach–Wiethe disease.
A meta‐analysis conducted in 2019 found only two clinical trials for the use of TMS in specific phobias, one of which explored anxiety and avoidance rates in individuals with acrophobia. Although the study found decreased rates in both anxiety and avoidance after two TMS sessions because of the limited number of studies and small sample size, few conclusions can be made. D-cycloserine (DCS), a partial N-methyl-D-aspartate agonist, is an additional investigational approach to augmentation specific phobias that a meta-analysis suggested had better outcomes and less symptom severity when utilized before initiating CBT. See also
Childhood phobia
List of phobias

References
External links

 Media related to Phobias at Wikimedia Commons
Social Anxiety at Curlie