Memory disturbance is different to memory loss (amnesia). In this section causes of abnormal or inappropriate memories are discussed.
Dementia is caused by degeneration of the brain in old age, and is associated with abnormal thought processes, poor memory and hallucinations.
Alzheimer disease (senile dementia or second childhood) is one of the most common forms of dementia in the elderly, and is characterised by loss of recent memory, loss of initiative, reduced physical activity, confusion, loss of orientation (patients become confused about where they are and dates), and then it gradually progresses to loss of speech, difficulty in swallowing (drooling results), stiff muscles, incontinence of both faeces and urine, and a bedridden state in which the patients are totally unaware of themselves or anything that is happening around them. It is caused by a faster than normal loss of nerve cells in the brain.
The female sex hormone oestrogen has an effect upon every cell in the body, not just the breast, uterus and other reproductive organs. During and after the menopause, the levels of oestrogen fluctuate irregularly, and then it disappears altogether. A lack of oestrogen will have effects on the brain that include memory disturbances. Hormone replacement therapy can correct the problem.
The organic brain syndrome is a result of severe emotional disturbance (eg. horror, fear) and causes memory disturbances, disorientation, poor logic and behavioural changes. Drug use, epilepsy, cancer outside the head and severe infections may also trigger this syndrome.
Some illegal drugs (e.g. heroin, marijuana) and prescribed narcotics and sedatives may affect memory. Long-term alcoholism may cause memory disturbances.