traumatic experiences. medications such as antidepressants has proven to be an effective way to block the effects of stress and to also promote neurogenesis. the medication phenytoin can also block stress caused to the hippocampus with the help of modulation of excitatory amino acids. preliminary findings indicate that cortisol may be helpful to reduce traumatic memory in ptsd. ptsd affects memory recall and accuracy. the more the traumatic event is brought to conscious awareness and recalled, the less accurate the memory. ptsd affects the verbal memory of the traumatic event, but does not affect the memory in general. one of the ways traumatic stress affects individuals is that the traumatic event tends to disrupt the stream of memories people obtain through life, creating memories that do not blend in with the rest. this has the effect of creating a split in identity as the person now has good memories they can attribute to one personality and bad memories the can attribute to the "other" personality. for example, a victim of childhood abuse can group their good and happy experiences under the "pleasant" personality and their abuse experiences under one "bad or wicked" personality. this then creates a split personality disorder. individuals with post traumatic stress disorder often have difficulty remembering facts, appointments and autobiographical details. the traumatic event can result in psychogenic amnesia and in the occurrence of intrusive recollections of the event. children with ptsd have deficits in cognitive processes essential for learning; their memory systems also under-performs those of normal children. a study using the rivermead behavioural memory test showed that individuals with ptsd scored lower than controls on the memory test, indicating a poorer general knowledge. the study revealed that 78% of ptsd patients under-performed, and where in the categories labelled "poor memory" or "impaired memory". ptsd patients were specifically worse at the prospective and orientation items on the rivermead behavioural memory test. a few studies done in the past proved that ptsd can cause cognition and brain structure changes that involve verbal declarative memory deficits. children that have experienced child abuse may according to neuropsychological testing experience a deficit in verbal declarative memory functioning. studies have been conducted on people that were involved in the vietnam war or the holocaust, returning iraq soldiers and people that also suffered from rape and childhood abuse. different tests were administered such as the selective reminding test, verbal learning test, paired associate recall, the california verbal new learning test, and the rivermead behavioral memory test. the test results showed that the returning iraq soldiers did have less verbal memory performance as compared to pre-deployment. the studies performed on the vietnam veterans that suffer from ptsd show that there are hippocampal changes in the brain associated with this disorder. the veterans with ptsd showed an 8% reduction in their right hippocampal volume. the patients that suffered from child abuse showed a 12% reduction in their mean left hippocampal volume. several of the studies has also shown that people with ptsd have deficits while performing verbal declarative memory task in their hippicampal. ptsd can affect several parts of the brain such as the amygdala, hippocampus, and the prefrontal cortex. the amygdala controls our memory and emotional processing; the hippocampus helps with organizing, storing and memory forming. hippocampus is the most sensitive area to stress. the prefrontal cortex helps with our expression and personality and helps regulate complex cognitive and our behavior functions. social anxiety disorder social anxiety disorder is an anxiety disorder consisting of overwhelming anxiety and excessive self-consciousness in everyday social situations. it is an extreme fear of being scrutinized and judged by others in social and/or performance situations. this fear about a situation can become so severe that it affects work, school, and other typical activities. social anxiety can be related to one situation (such as talking to people) or it can be much more broad, where a person experiences anxiety around everyone except family members. people with social anxiety disorder have a constant, chronic fear of being watched and judged by peers and strangers, and of doing something that will embarrass them. people with this may physically feel sick from the situation, even when the situation is non-threatening. physical symptoms of the disorder include blushing, profuse sweating, trembling, nausea or abdominal distress, rapid heartbeat, shortness of breath, dizziness or lightheadedness, headaches, and feelings of detachment. development of low self-esteem, poor social skills, and trouble being assertive are also common signs of social anxiety disorder. social anxiety disorder can be treated with many different types of therapy and medication. exposure therapy is an effective method of treating social anxiety. in exposure therapy a patient is presented with situations that they are afraid of, gradually building up to facing the situation that the patient fears most. this type of therapy helps the patient learn new techniques to cope with different situations that they fear. role-playing has proven effective for the treatment or social anxiety. role-playing therapy helps to boost individuals' confidence relating to other people and helps increase social skills. medication is another effective method for treating social anxiety. antidepressants, beta blockers, and anti-anxiety medications are the most commonly prescribed types of medication to treat social anxiety. moreover, there are new approaches to treat phobias and enhance exposure therapy with glucocorticoids. social phobics display a tendency to recall negative emotions about a situation when asked to recall the event. their emotions typically revolve around themselves, with no recollection of other people's environments. social anxiety results in negative aspects of the event to be remembered, leading to a biased opinion of the situation from the perspective of the social phobic compared to the non-social phobic. social phobics typically displayed better recall than control participants. however, individuals with social anxiety recalled angry faces rather than happy or neutral faces better than control participants. obsessive-compulsive disorder obsessive-compulsive disorder (ocd) involves both obsessions and compulsions that disrupt daily routines and activities. the obsessions include recurrent unwanted thoughts that cause compulsions, including repetitive behaviors. individuals with ocd may realize that their obsessions are not normal and try to stop their actions, but this only increases the person's anxiety towards the situation, and has an adverse effect. ocd often revolves around themes in one's life; for example, fear of coming in contact with germs (obsession). to deal with the fear of germs one may compulsively wash their hands until they are chapped. ocd is a constituent of many other disorders including autism, tourette's syndrome, and frontal lobe lesions. a person that shows a constant need to complete a certain "ritual", or is constantly plagued with unwelcome thoughts, may suffer from ocd. themes of obsessions include fear of germs or dirt, having things orderly and symmetrical, and sexual thoughts and images. signs of obsessions: fear of being contaminated which leads to avoidance of shaking hands with others, or touching items others have touched; doubts that you've completed tasks such as locking doors or turning appliances off; skin conditions due to excessive washing of one's hands; stress when items are not orderly or neat; thoughts about shouting obscenities or acting inappropriately; replaying pornographic images in one's head; compulsions follow the theme of the obsessions, and are repetitive behaviors that individuals with ocd feel will diminish the effect of the obsession. compulsions also follow the theme, including hand washing, cleaning, performing actions repeatedly, or extreme orderliness. signs of compulsions: washing hands until skin is damaged; counting in certain patterns; silently repeating a prayer, word or phrase; arranging food items so that everything faces the same way; checking locks repeatedly to make sure everything is locked; behavior therapy has proven to be an effective method for treating ocd. patients are exposed to the theme that is typically avoided, while being restricted from performing their usual anxiety reducing rituals. behavior therapy rarely eliminates ocd, but it helps to reduce the signs and symptoms. with medication, this reduction of the disorder is even more evident. antidepressants are usually the first prescribed medication to a patient with ocd. medications that treat ocd typically inhibit the reuptake of serotonin. obsessive-compulsive individuals have difficulty forgetting unwanted thoughts. when they encode this information into memory they encode it as a neutral or positive thought. this is inconsistent with what a person without ocd would think about this thought, leading the individual with ocd to continue displaying their specific "ritual" to help deal with their anxiety. when asked to forget information they have encoded, ocd patients have difficulty forgetting what they are told to forget only when the subject is negative. individuals not affected by ocd do not show this tendency. researchers have proposed a general deficit hypothesis for memory related problems in ocd. there are limited studies investigating this hypothesis. these studies propose that memory is enhanced for menacing events that have occurred during the individuals life. for example, a study demonstrated that individuals with ocd exhibit exceptional recall for previously encountered events, but only when the event promoted anxiety in the individual.