Taking certain medications, ignoring medical conditions like depression, or not getting enough vitamin B12 can each contribute to memory loss. But you can take steps now to reduce or reverse memory problems. Here are three ways you can lose your memory, and what you can do to stop it from happening in the first place.
Although older adults make up only 12 percent of the U.S. population, they receive about 30 percent of all prescriptions written in this country. Unfortunately, as people age, natural changes within the body make adverse effects from medications more likely.
For example, the kidneys may not remove drugs from the bloodstream as quickly as in younger adults, and drug metabolism in the liver may be slowed. In addition, a greater ratio of fat to muscle increases the time it takes to eliminate some drugs from the body. Above all, older adults on average take more than five prescription drugs and three over-the-counter drugs at the same time, significantly raising the risk of drug interactions. In geriatric clinics, the most common cause of reversible dementia is an adverse reaction to medication.
A class of medications called anticholinergics is known to cause cognitive problems in older people. Several commonly used medications are anticholinergics, including certain treatments for allergies, anxiety, asthma, depression, overactive bladder, pain, inflammation, and Parkinson’s disease. They are often an ingredient in “p.m.” sleeping pills sold over the counter. Some sedatives and sleep medications also can cause memory problems or even accelerate cognitive decline among people with Alzheimer’s disease.
Alcohol is another common drug implicated in dementia. As is often the case with other drugs, the negative effects of alcohol on a person’s intellectual abilities can frequently be reversed by abstinence. Chronic alcohol abuse, however, may lead to permanent damage; it is not clear whether this is due to the alcohol itself or to associated dietary insufficiency and head trauma.
2. Ignoring depression
The cognitive changes of dementia—impairment of memory, learning, attention and concentration—can also occur in people who are depressed, making the diagnosis of dementia more difficult. In fact, depression and cognitive decline often occur together.
A person is more likely to be suffering from depression than dementia if he or she has a prior history of psychiatric illness, a sudden onset of cognitive symptoms, difficulty sleeping, or a rapid decline in the ability to perform everyday activities. Because depression and dementia can be difficult to distinguish, a physician may suggest starting antidepressant therapy and then reassess the patient for dementia several months later.
3. Not treating certain medical conditions
A number of medical conditions can lead to memory loss, and in some instances, treating the underlying illness can reverse or reduce the memory deficit. These conditions include:
Hormonal imbalances from thyroid disease or Cushing’s disease (an overproduction of steroid hormones by the adrenal glands) 
Deficiencies of certain vitamins, especially vitamin B12 
Infectious diseases such as AIDS, syphilis, and chronic meningitis resulting from fungal infections or tuberculosisA brain tumor in the frontal or temporal lobe of the cerebral cortex 
Subdural hematomas (a collection of blood between the skull and the brain) 
Normal-pressure hydrocephalus (from excess fluid in the brain)
