Types * Anterograde<unk>  is the inability to create new memories due to brain damage, while long-term memories from before the event remain intact. The brain damage can be caused by the effects of long-term alcoholism, severe malnutrition, stroke, head trauma, encephalitis, surgery, Wernicke–Korsakoff syndrome, cerebrovascular events, anoxia or other trauma. The two brain regions related with this condition are medial temporal lobe and medial diencephalon. Anterograde<unk>  cannot be treated with pharmacological methods due to neuronal loss. However, treatment exists in educating patients to define their daily routines and after several steps they begin to benefit from their procedural memory. Procedural memory can be intact even when other forms of memory is not, although not always the case. Likewise, social and emotional support is critical to improving quality of life for those suffering from anterograde<unk> . Fentanyl use by opioid users has been identified as a potential cause in a cluster of cases that occurred in Boston, MA. * Retrograde<unk>  is inability to recall memories before onset of<unk> . One may be able to encode new memories after the incident. Retrograde is usually caused by head trauma or brain damage to parts of the brain besides the hippocampus. The hippocampus is responsible for encoding new memory. Episodic memory is more likely to be affected than semantic memory. The damage is usually caused by head trauma, cerebrovascular accident, stroke, tumor, hypoxia, encephalitis, or chronic alcoholism. People suffering from retrograde<unk>  are more likely to remember general knowledge rather than specifics. Recent memories are less likely to be recovered, but older memories will be easier to recall due to strengthening over time. Retrograde<unk>  is usually temporary and can be treated by exposing them to memories from the loss. Another type of consolidation (process by which memories become stable in the brain) occurs over much longer periods of time/days, weeks, months and years and likely involves transfer of information from the hippocampus to more permanent storage site in the cortex. The operation of this longer-term consolidation process is seen in the retrograde<unk>  of patients with hippocampal damage who can recall memories from childhood relatively normally, but are impaired when recalling experiences that occurred just a few years prior to the time they became<unk> . (Kirwan et al.,2008)In the case of LSJ, her case shows that retrograde<unk>  can affect many different parts of knowledge. LSJ was not able to remember things from her child or adult life. She was not able to remember things that most people pick up in everyday life such as logos or the names of common songs. *Post-traumatic<unk>  is generally due to a head injury (example: a fall, a knock on the head). Traumatic<unk>  is often transient, but may be permanent or either anterograde, retrograde, or mixed type. The extent of the period covered by the<unk>  is related to the degree of injury and may give an indication of the prognosis for recovery of other functions. Mild trauma, such as a car accident that results in no more than mild whiplash, might cause the occupant of a car to have no memory of the moments just before the accident due to a brief interruption in the short/long-term memory transfer mechanism. The sufferer may also lose knowledge of who people are. Having longer periods of<unk>  or consciousness after an injury may be an indication that recovery from remaining concussion symptoms will take much longer. *Dissociative<unk>  results from a psychological cause as opposed to direct damage to the brain caused by head injury, physical trauma or disease, which is known as organic<unk> . Individuals with organic<unk>  have difficulty with emotion expression as well as undermining the seriousness of their condition. The damage to the memory is permanent. Dissociative<unk>  can include: *Repressed memory is the inability to recall information, usually about stressful or traumatic events in persons' lives, such as a violent attack or disaster. The memory is stored in long-term memory, but access to it is impaired because of psychological defense mechanisms. Persons retain the capacity to learn new information and there may be some later partial or complete recovery of memory. Formerly known as "Psychogenic<unk> ". *Dissociative fugue (formerly psychogenic fugue) is also known as fugue state. It is caused by psychological trauma, is usually temporary and unresolved, and therefore, may return. It must exist outside the influence of pre-existing medical conditions, such as a lobotomy, and immediate influence of any mind-altering substances, such as alcohol or drugs. An individual with dissociative fugue disorder either completely forgets or is confused about their identity, and may even assume a new one. They can travel hundreds miles from their home or work; they can also engage in other uncharacteristic, and occasionally unsafe, behavior. For example, two men in a study of five individuals with dissociative fugue had engaged in criminal activity while in their fugue state, having had no criminal record before the episodes. While popular in fiction, this type of<unk>  is extremely rare. *Posthypnotic<unk>  occurs when events during hypnosis are forgotten, or where memories are unable to be recalled. The failure to remember those events is induced by suggestions made during the hypnosis. Some characteristics of posthypnotic<unk>  include inability to remember specific events while under hypnotic influence, reversibility, and having no relation between the implicit and explicit memory. Research has shown that there could be selectivity with<unk>  when posthypnotic<unk>  occurs. *Lacunar<unk>  is the loss of memory about one specific event. It is a type of<unk>  that leaves a lacuna (a gap) in the record of memory in the cortex region of the brain. The cause of this type of<unk>  is the result of brain damage to the limbic system which control our memories and emotions. *Childhood<unk>  (also known as infantile<unk>  is the common inability to remember events from one's own childhood. Sigmund Freud notoriously attributed this to sexual repression, while modern scientific approaches generally attribute it to aspects of brain development or developmental psychology, including language development, which may be why people do not easily remember pre-language events. Some research states that most adults cannot remember memories as early as two or three years old. Research suggests there are cultural influences that affect memories that are recalled. Researchers have found that implicit memories cannot be recalled or described. Remembering how to play the piano is a common example of implicit memory, as are walking, speaking, and other everyday activities that would be difficult to focus on if they had to be relearned every time one got up in the morning. Explicit memories, on the other hand, can be recalled and described in words. Remembering the first time meeting a teacher is an example of an explicit memory. *Transient global<unk>  is a well-described medical and clinical phenomenon. This form of<unk>  is distinct in that abnormalities in the hippocampus can sometimes be visualized using a special form of magnetic resonance imaging of the brain known as diffusion-weighted imaging (DWI). Symptoms typically last for less than a day and there is often no clear precipitating factor or any other neurological deficits. The cause of this syndrome is not clear. The hypothesis of the syndrome includes transient reduced blood flow, possible seizure or an atypical type of a migraine. Patients are typically<unk> estic of events more than a few minutes in the past, though immediate recall is usually preserved. *Source<unk>  is the inability to remember where, when or how previously learned information has been acquired, while retaining the factual knowledge. When individuals are unable to remember, false memories can occur and cause great confusion. *Korsakoff's syndrome can result from long-term alcoholism or malnutrition. It is caused by brain damage due to a vitamin B1 deficiency and will be progressive if alcohol intake and nutrition pattern are not modified. Other neurological problems are likely to be present in combination with this type of<unk> , such as problems with the medial temporal lobe and frontal lobe dysfunction. Korsakoff's syndrome is also known to be connected with confabulation. The person's short-term memory may appear to be normal, but the person may have a difficult time attempting to recall a past story, or with unrelated words, as well as complicated patterns. Korsakoff's syndrome is unique because it involves both anterograde and retrograde<unk> . *Drug-induced<unk>  is intentionally caused by injection of an<unk> estic drug to help a patient forget surgery or medical procedures, particularly those not performed under full anesthesia, or likely to be particularly traumatic. Such drugs are also referred to as "premedicants". Most commonly, a 2-halogenated benzodiazepine such as midazolam or flunitrazepam is the drug of choice, although other strongly<unk> estic drugs such as propofol or scopolamine may also be used for this application. Memories of the short time-frame in which the procedure was performed are permanently lost or at least substantially reduced, but once the drug wears off, memory is no longer affected. *Situation-specific<unk>  can arise in a variety of circumstances
Amnesia
Snatiation
Paranoia
Anhedonia
Allomnesia
Sexual anhedonia
Dyssomnia
Alexithymia