I've read anecdotal reports associating statins with memory loss, and I'm aware of an ongoing study at the University of California, San Diego (UCSD), that is investigating the effects of these drugs on thinking, mood, behavior, and quality of life. The same researchers have also been collecting reports about other side effects that patients attribute to statins, including peripheral neuropathy (tingling and numbness or burning pain), headaches, joint pains, and abdominal pain, problems with sleep and with sexual function, fatigue, dizziness, a sense of detachment, swelling, shortness of breath, changes in vision, temperature regulation, blood sugar, blood pressure, weight, as well as hunger, breast enlargement, dry skin, rashes, nausea, upset stomach, bleeding, and ringing in ears or other noises. Based on some 5,000 reports accumulated by early 2008, memory problems were the second most common side effect reported. (Muscle aches were first.) Memory returned to normal when affected patients discontinued the statins.
Statins are known to cause muscle aches and liver dysfunction; warnings of both possibilities are prominent in the printed instructions patients get when they pick up their prescriptions. So far, no causal link between the drugs and memory loss has been demonstrated. Worldwide, some 25 million people take these cholesterol-lowering agents. With that denominator, even a few thousand reports of memory loss represent only a tiny fraction of patients.
How statins might affect memory isn't known. But since there's lots of cholesterol in the brain, lowering levels throughout the body could impact brain function.
In general, I wouldn't worry about the effect of statins on memory. But if you're taking the drug and find that you're becoming forgetful, tell your doctor. Lowering your dose may help. Or your physician might suggest going off the drug for a few weeks to see if your memory improves. If it does, you should discuss with your physician other approaches to cholesterol control.
Remember, it is possible to lower cholesterol without medication: get at least 30 minutes a day of aerobic exercise and reduce the amount of saturated fat and trans-fats in your diet. Other beneficial measures include drinking green tea, eating one clove of garlic per day (diced or crushed in food), and consuming more soluble fiber (such as oat bran), foods rich in omega-3 fatty acids (good sources include salmon, sardines and walnuts) and plenty of leafy greens and fresh fruits.
If lifestyle changes don't help, you could try red rice yeast (Monascus purpureus), a source of naturally occurring statins, before resorting to pharmaceutical versions. Because it delivers a mix of those compounds rather than a single molecule, red rice yeast is less likely to cause side effects.
Andrew Weil, M.D.