With just 3 protons, you could perhaps be excused for thinking there isn’t much to lithium. But it turns out it’s good for a lot more than just batteries. Lithium has been a go-to medication for bipolar disorder for almost half a century, and we’re still figuring out how it works and what it can do.
Lithium’s main role as far as we’re concerned is neuroprotection. It accomplishes this by several avenues. First, it decreases cells’ supplies of inositol by preventing it from recycling old inositol. Normally inositol causes growth cones, areas of neurons which are growing out to form new connections, to collapse. By getting rid of the excess, lithium promoted neural growth and survival. Another way lithium is neuroprotective is that it inhibits a number of signals and pathways that promote apotosis, or programmed cell death, including p53, which has been found to be involved in neurodegeneration due to Alzheimer’s disease and strokes. It’s also proactive, increasing production of BDNF, or brain derived neurotrophic factor. Neurotropic factors are signals produced to promote both survival of neurons and their growth and proliferation. BDNF specifically is known to be part of the mechanism by which some antidepressant and anti anxiety medications work.
Unfortunately, it isn’t all blue skies with lithium. As great an idea as it may seem to start taking a daily bit of lithium just to be safe, lithium isn’t without its drawbacks. It has a low therapeutic index, which means that there isn’t a big difference between the amount that helps you and the amount that hurts you. Without a doctor keeping an eye on you and your dosage, you can reach lithium toxicity pretty easily, and it isn’t fun. Acute toxicity can cause dizziness, seizures, or even coma, and even trickier is chronic toxicity when you take just a bit too much each day and it builds up. That can cause muscle tremors, kidney failure, and psychosis. So as lovely a metal as lithium is, it’s still yet another medication to be careful with.