Is an underlying condition causing your fuzzy thinking?

The top five causes you may be overlooking.

You know the feeling: you can’t find a particular word, remember someone’s name, or concentrate the way you once did. Is it just aging, or is something else to blame? “It’s easy to underestimate how underlying conditions affect memory and thinking, and they are often overlooked,” says Dr. Shreya Raj, a neuropsychiatrist with the Center for Brain/Mind Medicine at Harvard-affiliated Brigham and Women’s Hospital.

Common causes

Dr. Raj points to five common and treatable underlying conditions that can impair thinking skills.

1. Medication side effects. Taking anticholinergics, which block the effects of a neurotransmitter responsible for stimulation and activity in the brain, may result in confusion. Among the many anticholinergic drugs are over-the-counter medications such as oxybutynin (Ditropan) for incontinence and diphenhydramine (Benadryl) for allergies, and prescription medications such as amitriptyline (Elavil) for depression and cyclobenzaprine (Flexeril) for muscle spasms. “In addition, any medication that has a sedative effect may make it hard to concentrate, such as pain or sleep medications,” says Dr. Raj.

2. Low B12. Vitamin B12 is essential for healthy blood and nerve function. We get B12 from eating meat, eggs, and milk and other dairy products. But as we age, it gets harder to absorb B12. This can cause abnormally low B12 levels in the blood and lead to fuzzy thinking and other symptoms, such as muscle weakness. Some people have a rare form of anemia that makes it very hard to absorb B12.

3. Excessive anxiety or depression. Both generalized anxiety disorder (when worry is excessive) and depression (feelings of extreme sadness or hopelessness that last more than two weeks) can cause fuzzy thinking. “These conditions interfere with your ability to attend to what’s going on around you, and you feel mentally exhausted. That can impair your ability to think clearly or make a decision,” says Dr. Raj.

4. Underactive thyroid gland. When your thyroid gland isn’t producing enough thyroid hormones—thyroxine (T4) and triiodothyronine (T3)—many body functions become sluggish, including brain function. This can lead to fuzzy thinking and forgetfulness.

5. Obstructive sleep apnea. Obstructive sleep apnea causes people to stop breathing periodically while they sleep. The classic symptom is daytime sleepiness. Another common symptom is loud snoring, often accompanied by gasping for breath. Sleep apnea puts you at risk for stroke and heart disease, and it can also cause fuzzy thinking.

What you should do

When trouble with concentration or memory interferes with your day, it’s probably time to talk to your primary care doctor. Report any additional symptoms you may be having, such as fatigue, muscle weakness, sadness, daytime sleepiness, or anxiety. You might need some blood tests to check your thyroid hormones or B12 levels (neither test is ordered routinely), or a sleep test if you have sleep apnea symptoms.

Often, treating an underlying condition can restore your clarity of thinking. “When we treat depression or sleep apnea, for example, we see a sudden improvement in memory and focus,” says Dr. Raj. “And if a medication side effect is the problem, changing the dose or type of drug may resolve the problem.”

If treating an underlying condition doesn’t sharpen thinking skills, your doctor may refer you to a neuropsychologist for formal tests of your thinking ability, particularly signs of dementia. Most of the time, however, people with fuzzy thinking do not have dementia.

Fuzz busters

woman-sleep-tired-bedWhen you’re struggling with fuzzy thinking, lifestyle changes like these can bring more clarity.

Get more sleep. Aim for seven to eight hours of sleep per night. “Older adults to tend to sleep less, but if you’re getting too little sleep, you won’t think as sharply as you could,” says Dr. Shreya Raj. Boost your Z’s by going to sleep and waking at the same time each day, and avoiding caffeine, particularly after noon.

Exercise more. Try to get 150 minutes of moderate-intensity activity per week, such as brisk walking. You’ll get more sleep and boost blood flow to the brain. Many studies have shown that aerobic exercise in particular improves thinking skills.

Change your diet. “Not eating healthfully makes you more sluggish, even in thinking. Studies have shown the Mediterranean diet may improve cognitive function,” says Dr. Raj. The diet includes fresh vegetables and fruits; whole grains; olive oil; nuts; legumes; fish; moderate amounts of poultry, eggs, and dairy; moderate amounts of red wine; and red meat only sparingly.

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