By Dr Ananya Mandal, MD
Amnesia is a form of memory loss that is usually temporary and affecting short term memory.
Common causes and risk factors of amnesia and memory loss include concomitant psychological problems, trauma or head injury and so forth. (1-6)
Concomitant psychological problems
Many patients with memory loss present with other emotional problems like depression, stress and anxiety.
In these patients memory loss is due to poor concentration and not noticing things rather than actual memory impairment.
Sleeping problems are also reasons for poor memory in these patients.
Trauma, head injury, epileptic seizure or stroke
These may lead to sudden memory loss or amnesia.
In stroke, some of the blood supply to a part of the brain is cut off. This causes the brain tissues to die.
If the patient forgets everything that happened before the incident it is called retrograde amnesia and if he or she forgets all that happened after the incident, it is called anterograde amnesia.
This type of acute or sudden amnesia is caused due to lack of adequate oxygen in certain parts of the brain.
Other causes of amnesia
Other causes of amnesia include:
- Thyroid problems – those with lower activities of the thyroid gland are at risk of memory loss
- Sedatives and some medications used against Parkinson’s disease may cause memory loss over time.
- Long term damage to the brain due to alcohol abuse. Korsakoff's psychosis is caused by long term alcohol abuse.
- Dietary or other deficiency of the vitamin B1 or thiamine may lead to amnesia.
- Transient global amnesia caused by problems with blood flow to part of the brain, which cause sudden episodes of memory loss that a person cannot remember afterwards.
- Psychogenic amnesia where the patient blocks out a part of his or her memory of an unpleasant event in the past. This makes them unable to remember important information.
- Infantile or childhood amnesia – Inability to remember events from early childhood. This may be due to psychological stress during that period of life.
- Tumors of the brain may lead to amnesia
- Brain infections like Lyme’s disease, syphilis or HIV/AIDS may lead to memory loss
- After certain types of brain surgery.
- After cancer chemotherapy, brain radiation or bone marrow transplant
- After Electroconvulsive therapy especially over long term.
- Slow decline of memory as seen in dementia caused by Alzheimer’s disease
- Memory loss may be seen in poorly controlled cases of bipolar disorder, or schizophrenia.
- Hormonal changes are responsible for memory loss. For example risk of memory loss rises with lower levels of estrogen in women after menopause. Elderly with high levels of corticosteroid are at risk of memory decline.
- General physical illness may affect concentration and memory.
Edited by April Cashin-Garbutt, BA Hons (Cantab)
What is amnesia?