What does research say about the relationship between lithium and memory?
Lithium slows cognitive decline in mild memory problems and early Alzheimer's disease, but for healthy people or as a preventive measure there is no evidence of memory improvement. If you use lithium for a psychiatric condition, discuss any memory complaints with your treating clinician, as these are often linked to your mood rather than the medication.
Lithium slows cognitive decline in people with mild memory complaints and early Alzheimer's disease. A meta-analysis of three randomised trials (232 participants) showed a significant effect in favour of lithium over placebo. In one of those trials, involving 45 people with mild cognitive decline, a biological marker of brain cell damage (phospho-tau) in the cerebrospinal fluid also fell after twelve months, while memory and attention scores improved. A separate small study in Alzheimer's patients found that an extremely low dose (300 micrograms per day, far below the usual psychiatric dose) stabilised decline on a cognitive test three months earlier than expected. That last study was small, so the results deserve cautious interpretation.
For people who already use lithium for a bipolar or unipolar disorder, the picture looks different. Several studies, including a double-blind cross-over experiment in 16 patients, found no measurable memory loss from lithium. What lithium does do is slow psychomotor speed, so you react and move slightly more slowly. Subjective memory complaints reported by patients are in practice more often associated with residual depressive symptoms than with lithium itself. The literature on this specific use is contradictory, partly because studies differ considerably in design and patient populations.
Animal research provides clues about a mechanism: in mice with an Alzheimer-like disease model, a low dose of lithium prevented memory decline, reduced the formation of harmful plaques in the brain, and increased a protein that supports brain cell growth. Findings in mice do not automatically apply to humans, but they point the way for further research.
Whether lithium also helps healthy people remember better has not been demonstrated. A review study concludes that cognitive benefits only appear to become visible when the nervous system is already under pressure, for example due to illness or stress. People who use lithium because of thyroid or kidney problems face a greater risk of side effects with long-term use; these should be monitored.
One meta-analysis of three randomised trials (n=232) forms the core of the evidence in Alzheimer/MCI. Additionally, there are two separate randomised trials, two reviews, a cross-over experiment, and one animal study. In the context of use for bipolar disorder, the findings are associative and contradictory.
Does a lithium deficiency increase the risk of dementia?
Research shows that lithium use is associated with lower rates of dementia, and in people with early memory problems there are initial indications that it may slow cognitive decline. Whether this also applies to advanced dementia remains unclear.
Does a low dose of lithium help protect the ageing brain?
There are preliminary indications that low doses of lithium may offer brain protection, but the evidence is still too thin and the risks are real enough that lithium should only be used under medical supervision.
What are the causes of memory loss?
Memory loss has many possible causes that differ greatly from one another. If you suddenly develop memory problems, always have them assessed by a doctor so that a treatable cause is not missed.
What does long-term stress do to your memory?
Long-term stress harms memory through measurable changes in the brain, and early-life stress raises the risk of memory problems later in life. The better you manage stress, the less damage that accumulation causes.
Why does your memory work less well as you get older?
Memory loss with ageing is a normal biological process with multiple clearly demonstrated causes, but you can slow it down: regular exercise and mental activity have the strongest evidence base.
How do you train your memory effectively?
Memory can be trained, but the smartest investment is regular exercise: that has the strongest and broadest support for cognition and memory. Targeted memory training helps, but less spectacularly than is often assumed.