While the news about advances in Alzheimer’s research has been steady over the past several years, including new treatment options that can potentially slow down cognitive decline, along with better ways of diagnosing Alzheimer’s at an earlier stage, there have not been gob smacking advances that have left researchers excited about the potential for real change in the way we diagnose and treat Alzheimer’s. But new research from Harvard Medical School and published in Nature, may dramatically alter the way scientists diagnose and treat Alzheimer’s going forward.

For the first time, researchers have confirmed that the metal lithium is naturally present in the brain and that levels of lithium may play an essential physiological role in the brain’s susceptibility to mild cognitive impairment and the more serious diagnosis of Alzheimer’s. Essentially, what both human and mouse studies now suggest is that low levels of lithium in the brain contribute to cognitive decline and that, at least in mouse studies, supplementation with a specific type of lithium can reverse memory loss. There is a long history of the use of lithium (which is nature’s lightest metal) in both food (apparently the original formulation of 7Up contained lithium, though it no longer does) and as a therapeutic treatment for mood disorders like bipolar disease (and yes, it’s also essential for the batteries that power our electric cars, phones, and computers). There is also research showing that in environments with higher levels of lithium (for example, in the drinking water), lower rates of dementia have been found in the populations. Lithium plays a vital role in maintaining connections and communication lines so that healthy neurons in the brain can communicate with each other. It’s considered the gold standard for treating psychiatric illnesses such as bipolar disorder, though it needs to be carefully monitored for toxicity.

What this new research out of Harvard suggests is that when naturally occurring levels of lithium in the brain decline, memory loss may begin to surface, along with such hallmarks of Alzheimer’s Disease as amyloid plaques and tau tangles. Researchers discovered that in parts of the brain affected by amyloid plaques, there are lower lithium levels, and that in people with mild cognitive impairment (which can progress to full-blown Alzheimer’s), lithium becomes tied up with the plaques, leaving less available for maintaining normal brain functions. Furthermore, in mouse experiments, falling lithium levels also correlated with accelerated brain deterioration, increased amyloid plaques, and more memory decline. In essence, lower lithium levels were not just a byproduct of Alzheimer’s but perhaps what initially drove the brain to succumb to the ravages of the disease.

Perhaps the most exciting news to come out of this research was found in the mouse studies, which demonstrated that a small, non-toxic dose of a particular type of lithium could reverse memory loss in mice. While not all mouse studies can be replicated in humans, this research does present the possibility that one day monitoring lithium levels through blood tests in humans could be a routine way to identify those at risk for Alzheimer’s and even delay or prevent its onset using targeted lithium supplementation. Researchers make clear that despite these very promising results, no one should take lithium supplements now as a way to address concerns about Alzheimer’s. But there likely will come a day when lithium screening will become the norm to identify those at risk and possibly treat those with symptoms. 

In the meantime, more work is advancing on currently available blood tests to diagnose Alzheimer’s, without potentially needing the costly and invasive PET scans or spinal taps that have previously confirmed a diagnosis. You may remember that this past spring, the FDA approved the first blood test for use in diagnosing Alzheimer’s. While this was a positive development, and the approved test did have a high level of specificity and validation, dementia specialists were left with uncertainty about how to use the test in clinical settings. Now, the Alzheimer’s Association has just announced clinical practice guidelines for the use of Alzheimer’s blood biomarker tests, and in some cases, the guidelines suggest the blood test alone could potentially confirm a diagnosis without needing to resort to more invasive confirmatory tests. This is an important step, given the availability of new treatment options that are most beneficial if started as early as possible. Specifically, it’s recommended that a blood test alone should only be used by dementia specialists who have already confirmed that the patient has cognitive impairment and has undergone a full clinical evaluation. In essence, the blood test alone should not be used on “the worried well” who have no symptoms but are concerned about their risk. It is also recommended that the blood test used by specialists have a high level of accuracy, which many currently on the market (or coming to market) may not have. There are risks to these blood tests, including false positives and false negatives, and potential discrimination against those who test positive. This is still an evolving area of research, and more changes and recommendations are likely to come in the near future. But for now, for those experiencing cognitive decline and under the care of specialists, getting a blood test to confirm an Alzheimer’s diagnosis may be an important step toward becoming eligible for new treatment options.