Why is lithium the gold standard for treatment in bipolar disorder? What makes it a particularly useful drug? And what does it do in terms of being effective in managing affective disorders?
To start it all off, Lithium is an old drug. It was first used for stones in the bladder way back in 1843, but it wasn’t until 1949 that John Cade discovered that it had anti-manic properties. Lithium’s mechanism has to do with the sodium-potassium levels in neurons. The sodium pump is responsible for potentiating the neuron to receive and amplify incoming messages. Lithium interferes with this process and thus reduces the potentiation of neurons, in effect, it stops certain messages from being relayed. I surmise that this results in the quieting of the manic mind which is firing on all cylinders. But it also works fairly well as an antidepressant. So much so that a randomized trial found no statistically significant difference between lithium and antidepressants in unipolar affective disorder. Lithium, it seems, works both sides of bipolar disorder with gold standard efficacy. It also is highly effective in reducing suicidal tendencies. The difference being a very significant 80%
But what about other effects that lithium has on the brain? I recently wrote a bit about it, but I’ll tread the waters again. Lithium has a restorative property to developmental differences in the hippocampus region of the brain. That region being responsible for emotional regulation and long term memory. So lithium has an advantage in both being a prophylactic treatment that treats the symptoms as well as a restorative role in increasing the brain volume of certain regions of the brain.
So why not lithium. It requires management. For starters, there is a narrow window of therapeutic lithium levels and toxic lithium levels. Therapeutic levels of lithium found in plasma are to be between 0.4 and 1.2 mmol L+ (millimolar of lithium ions), but toxic levels are at 1.5 mmol L+. This means that going on lithium is an investment in time and access to monitoring facilities. You can’t just take it and check the side effects of it, you need to go and have blood tests regularly until you’re in the therapeutic range. If someone is highly unstable, lithium is hardly a drug of choice given that the tests might not be followed through or the titration period will be ignored.
In addition to access to testing facilities, the narrow band of therapeutic versus toxic levels means that one must be careful of things like sweating too much, becoming dehydrated, drinking too much caffeine. Sweating and dehydration increases the lithium levels in the body, where as caffeine reduces them. Life style changes are required for this drug to work. It’s not set-and-forget like lamictal, it’s a drug that requires proactive monitoring of electrolytes, hydration, exercise, weight gain, and food intake.
But despite all of that, it works. And it works very well. I’m only into my first week on it, and I’m being very careful and being the good patient, but I wonder how long that can last. But in the mean time, I have noticed a decrease in my suicidal ideation, so it might be starting to work. Here’s hoping Lithium is the drug of choice. It’s the 11th drug that I’ve been put on in the past 11 months if you count all the benzos, so here’s hoping that it’s the last drug that they put me on.