9 Medical Reasons Your Short-Term Memory Is Getting Worse

Updated: Oct. 10, 2022

From medications to sleep, there are simple explanations—and fixes—for your forgetfulness.

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What is short-term memory?

Short-term memory is the type of memory you need to accomplish your immediate goals, explains Patrick Lyden, MD, chair of the department of neurology at Cedars-Sinai. That may be working your way through tasks during the workday, remembering someone’s name, email, or phone number, or recalling where you tossed your keys when you got home.

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Where is it located in the brain?

When someone rattles off their phone number, you file it away in brain circuits that include the hippocampus (your memory center) and the amygdala (your emotional hub). Depending on how important the short-term memory item may be (your address, someone you call all the time), it can be converted into long-term memory, says Dr. Lyden. (Want to work on your memory? Try these morning brain boosters to stay sharp.)

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How does short-term memory work?

Short-term memory isn’t just about being able to quickly recall new info; there are three phases. “You have to register the information, store the information, and retrieve the information,” says Dr. Lyden. Registering means that you’re paying attention in the first place. Storing the info means you’ve filed it away in your brain. Retrieval is the ability to access the memory again. Any of these steps can break down, he says.

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Is your memory OK?

Many people assume they have a memory problem when the explanation is something else entirely, says Dr. Lyden. Maybe you’re not paying attention because you’re gazing at your phone or texting, for example. The first step to figuring out if something is going on is to “pay closer attention,” he says. Repeat the new information three times to commit it to memory.

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When it may be time to worry

If you can’t pass the “pay attention test” despite repeating the information, your next step, advises Dr. Lyden, is to determine if your problem is storing new memories or retrieving them. If you’re having a problem remembering a new acquaintance’s name, ask them to give you three choices—like Carrie, Lauren, or Janet. If your problem is storing new memories, you won’t be able to remember. But if your problem is retrieval, you’ll remember that her name is Janet once you hear the correct name.

Having trouble with retrieving a short-term memory isn’t as serious as being unable to store them. “The storage problem is a serious problem, and you should see a neurologist,” he says.

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Blood flow is good for your brain—it keeps it young. “Exercising boosts blood flow to your brain. If you stay active, you’ll have a better memory,” says Daniel G. Amen, MD, author of Memory Rescue: Supercharge Your Brain, Reverse Memory Loss, and Remember What Matters Most. Dr. Lyden suggests daily exercise and it doesn’t have to be intense. “A half-mile or mile run daily is better than a 10-mile run one day a week,” he says.

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Substance abuse

With the legalization of recreational marijuana in some states, many people assume that the drug isn’t harmful. However, Dr. Amen calls this a toxin that impairs memory. “Marijuana lowers every area of the brain and ages it. On average, pot smokers have brains three years older than non-smokers,” he says. Alcohol abuse can also harm your memory.

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Mental health conditions

People tend to miss their own depression. But if you’re suffering from depression, anxiety, or chronic stress, get help or your memory can also pay the price. “These conditions may all hurt the brain,” says Dr. Amen. Getting relief will not only improve your life and outlook but save your brain. (Here are 8 hidden signs of depression to watch for.)

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Lack of sleep

When considering short-term memory loss causes, poor sleep is a big one. “If you don’t sleep seven hours a night or more, you’ll be in trouble. Your brain cleans itself at night. When you don’t get enough, it’s like the trash crew didn’t come to clean up,” says Dr. Amen.

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Lyme disease

Lyme disease is transmitted through a tick bite, and causes early symptoms like fever, chills, headache, and fatigue, according to the Centers for Disease Control and Prevention (CDC). Later on, without treatment, some people also may notice short-term memory problems. Dr. Amen points out this may include trouble with attention, focus, and organization.

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Before you panic, there’s some good news: “The vast majority of people who are healthy will not have a degenerative neurological condition causing short-term memory loss,” says Dr. Lyden. But dementia or Alzheimer’s is a possibility in some groups. If you’re over 60 and have risk factors like diabetes, high blood pressure, or obesity, then you may be more prone to problems and need to be evaluated, he says.

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If you lead a healthy lifestyle, eat right, exercise, and go easy on alcohol and other substances that can harm memory, yet you still feel like your memory if failing, talk to your doctor about your medications—prescription and over-the-counter, advises Dr. Lyden. Cholesterol drugs, painkillers, high blood pressure pills, and sleeping pills are among the drugs that can trigger memory issues.

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When you have an underactive thyroid, everything in your body runs slower. Your digestion will slow and you can become constipated; cell growth slows and can lead to hair loss; your metabolism becomes sluggish, triggering weight gain. And you may be plagued by muddied thinking or forgetfulness. Often, medication to restore thyroid hormones can help alleviate symptoms and help you feel better all over.

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A poor diet

Inflammation is bad for your body and your brain. “The higher the inflammation levels in your body, the worse your memory will be,” says Dr. Amen. Eating an anti-inflammatory diet, like the Mediterranean diet, and avoiding foods that increase it (highly processed foods, loads of sugar) is key. He also recommends taking fish oil and probiotics.

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When to seek help

Along with the self-test mentioned earlier, think about how you perceive your short-term memory. Ask yourself: Is it getting progressively worse? Is it worse than 10 years ago? Are other people noticing a problem? “Those are things you should take seriously,” says Dr. Amen.

Next, check out the 50 habits that reduce your risk of dementia.