are also effective in GAD and PTSD treatment. However, there is a higher chance of experiencing adverse effects than the other anti-anxiety medications. Beta-adrenoceptor antagonists Propranolol is originally used for heart diseases. It can also be used to treat anxiety with symptoms like tremor or increased heart rate. They work on the nervous system and alleviate the symptoms as a relief. Mechanism of Action Selective serotonin reuptake inhibitors (SSRI) and serotonin and norepinephrine reuptake inhibitors (SNRI) Both SSRIs and SNRIs are reuptake inhibitors of a class of nerve signal transduction chemical called neurotransmitters. Serotonin and norepinephrine are neurotransmitters that are related to nervous control in mood regulation. The level of neurotransmitters are regulated by the nerve through reuptake to avoid accumulation of the neurotransmitter at the endings of nerve fiber. By reuptaking the produced neurotransmitter, the level will go back down and ready to go back up upon excitation from a new nerve signal. However the level of patients with anxiety disorders are usually low or their nerve fibers are insensitive to the neurotransmitters. SSRIs and SNRIs will then block the channel of reuptake and increase the level of the neurotransmitter. The nerve fibers will originally inhibit further production of neurotransmitters upon the increase. However the prolonged increase will eventually desensitize the nerve about the change in level. Therefore, the action of both SSRIs and SNRIs will take 4–6 weeks to exert their full effect. Benzodiazepine Benzodiazepines bind selectively to the GABA receptor, which is the receptor protein found in the nervous system and is in control of the nervous response. Benzodiazepine will increase the entry of chloride ions into the cells by improving the binding between GABA and GABA receptors and then the better opening of the channel for chloride ion passage. The high level of chloride ion inside the nerve cells makes the nerve more difficult to depolarize and inhibit further nerve signal transduction. The excitability of the nerves then reduces and the nervous system slows down. Therefore, the drug can alleviate symptoms of anxiety disorder and make the person less nervous. Clinical use Selective serotonin reuptake inhibitors Selective serotonin reuptake inhibitors (SSRIs) are a class of medications used in the treatment of depression, anxiety disorders, OCD and some personality disorders. SSRIs are the first-line anti-anxiety medications. Serotonin is one of the crucial neurotransmitters in mood enhancement, and increasing serotonin level produces an anti-anxiety effect. SSRIs increase the