An anxiolytic (; also antipanic or anti-anxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxiety disorders and their related psychological and physical symptoms. Nature of anxiety Anxiety is a naturally-occurring emotion and an innate response of the body to the environmental stimuli. Mild to moderate anxiety would increase level of performance. However, when anxiety levels exceed the tolerability of a person, anxiety disorders may occur. People with anxiety disorders can exhibit fear responses such as defensive behaviors, high levels of alertness and negative emotions, without external stimuli which induce anxiety within an individual. Those with anxiety disorders are also often found to have concurrent psychological disorders, most commonly depression. Anxiety disorders are divided into 6 types in clinical recognition. They are as follows. Different types of anxiety disorders will share some general symptoms while having their own distinctive symptoms. This explains why people with different types of anxiety disorders will respond differently to different classes of anti-anxiety medications. Etiology The etiology of anxiety disorder remains unknown. There are several contributing factors that are still yet to be proved to cause anxiety disorders. These factors include childhood anxiety, drug induction by central stimulant drugs, metabolic diseases or having depressive disorder. Medications Anti-anxiety medication is any drug that can be taken or prescribed for the treatment of anxiety disorders, which may be mediated by neurotransmitters like norepinephrine, serotonin, dopamine, and gamma-aminobutyric acid (GABA) in the central nervous system. Anti-anxiety medication can be classified into six types according to their different mechanisms: antidepressants, benzodiazepines, buspirone, antiepileptics, antipsychotics, and beta blockers. Antidepressants including selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCA), Monoamine oxidase inhibitor (MAOI). SSRIs are used in all types of anxiety disorders while SNRIs are used for generalized anxiety disorder (GAD). Both of them are considered as first-line anti-anxiety medications. TCAs are second-line treatment as they cause more significant adverse effects when compared to the first-line treatment. Benzodiazepines are effective in emergent and short-term treatment of anxiety disorders due to their fast onset but carry the risk dependence. Buspirone is indicated for GAD, which has much slower onset but with the advantage of less sedating and withdrawal effects. Anti-anxiety medications may cause adverse reactions, addiction, and withdrawal symptoms. History The first monoamine oxidase inhibitor (MAOI), iproniazid,