Memory loss can affect a person's ability to form new memories or recall stored memories. The U.S. Food and Drug Administration (FDA) notes that while normal aging can cause memory problems, illnesses can result in severe memory loss. Some of the memory loss caused by these illnesses can improve with treatment; however, some patients may never regain their lost memories.
Dementia
Dementia, a neurological condition, causes progressive deterioration of brain functions, which includes memory. The Mayo Clinic states that Alzheimer's disease is the most common form of dementia. The memory loss starts with problems remembering recent events. As the disorder progresses, patients also have difficulty remembering information about themselves. The National Institutes of Health (NIH) notes that this memory loss causes patients to lose sense of who they are. By the last stage of dementia, patients do not remember their family members.
Stroke
Caused by either a burst or blocked blood vessel, a stroke can also cause memory loss. The NIH states that, depending on the location of the stroke, patients can have confusion or memory loss. For example, if a patient has a stroke on her temporal lobe, she can have problems with either short-term memory or long-term memory. The memory loss may be permanent if damage occurs to the brain tissue, rather than just damage to the blood vessel.
Depression
A mood disorder that causes severe sadness and feelings of guilt, depression affects patients' attention. If a person cannot concentrate, it can have an effect on his ability to form new memories. Ranjit Mani, MD of the FDA notes that the memory loss of depression may improve by treating the depression, such as with medication or psychotherapy.
Thyroid Problems
If a person's thyroid does not function properly, memory loss may occur. The FDA states that an underactive thyroid, termed hypothyroidism, can cause problems with memory and concentration. These symptoms can also occur with an overactive thyroid, also called hyperthyroidism. The Mayo Clinic adds that hypothyroidism can also cause depression.
Infections
Certain infections, which damage brain tissue, may also result in memory loss. Some of these infections are sexually transmitted, like herpes, HIV and syphilis. For example, the NIH notes in the tertiary, or final, stage of syphilis, the infection spreads up to the brain, causing memory loss. The FDA adds that tuberculosis can also cause memory loss.
