The onset of psychogenic amnesia can be either global (i.e., individual forgets all history) or situation specific (i.e., individual is unable to retrieve memories of specific situations).Patients experiencing psychogenic amnesia have impaired episodic memory, instances of wandering and traveling, and acceptance of a new identity as a result of inaccessible memories pertaining to their previous identity.Recent research has begun to investigate the effects of stress and fear-inducing situations with the onset of RA. Long-term potentiation (LTP) is the process by which there is a signal transmission between neurons after the activation of a neuron, which has been known to play a strong role in the hippocampus in learning and memory. Common changes in the hippocampus have been found to be related to stress and induced LTP. The commonalities support the idea that variations of stress can play a role in producing new memories as well as the onset of RA for other memories. The amygdala plays a crucial role in memory and can be affected by emotional stimuli, evoking RA.Studies of specific cases, such as AMN, support evidence  of traumatic experiences as a plausible cause of RA. AMN escaped a small fire in his house, did not inhale any smoke, and had no brain damage. Nevertheless, he was unable to recall autobiographical knowledge the next day. This case shows that RA can occur in the absence of structural brain damage.After a traumatic head injury, emotional disturbances can occur at three different levels: neurological, reactionary, and long-term disturbances. Neurological disturbances can change emotional and motivational responses.
Brunner syndrome is a rare genetic disorder associated with a mutation in the MAOA gene. It is characterized by lower than average IQ (typically about 85), problematic impulsive behavior (such as pyromania, hypersexuality and violence), sleep disorders and mood swings. It was identified in fourteen males from one family in 1993. It has since been discovered in  additional families. Signs and symptoms
Causes
Brunner syndrome is caused by a monoamine oxidase A (MAOA) deficiency, which leads to an excess of monoamines in the brain, such as serotonin, dopamine, and norepinephrine (noradrenaline). In both mice and humans, a mutation was located on the eighth exon of the MAO-A gene, which created a dysfunctional MAO-A gene. The regular function of MAO-A, breaking down monoamines, is disrupted, and monoamines build up within the brain. Mice that lacked a functional MAO-A gene displayed higher levels of aggression, in comparison to mice with a functional MAO-A gene. Diagnosis
Upon suspicion of Brunner syndrome and after having eliminated other potential suspects via means of differential diagnosis, Brunner syndrome is diagnosed by genetic testing for specific mutations of the MAOA gene. Since the syndrome is so rare, it is usually only suspected and tested for if there are other diagnosed instances of the syndrome in ones direct family. Treatment
Progesterone & Rauwolfia serpentina (containing Reserpine) are a possible treatment as they both increase MAO-A activity. History
Brunner Syndrome was described in 1993 by H.G. Brunner and his colleagues upon the discovery of a particular genetic defect in male members of a large Dutch family.