The question, and the bottom line
Does lithium increase the risk of having a seizure? In medical lingo this is referred to as “lowering seizure threshold.” Bottom line: from what I can find that looks at actual data, not quoting someone else’s review, there is no impact or maybe even a benefit from therapeutic levels of lithium. If those levels get too, that’s bad for many reasons, and increased risk of seizures is one of those reasons.
Quoting references without looking at real data
Many references put lithium on the list of medications that lower seizure threshold, along with antipsychotics and antidepressants. (It gets complicated for the antidepressant bupropion, where the immediate release is worse but the sustained releases are no worse than other antidepressants.Dunner )
But where is the specific reference for this belief? I can’t find one, frankly, after about 30 minutes of searching the literature. Everyone references another review that says lithium lowers seizure threshold but I can’t find the direct work that specifies how this concern about lithium has been identified. I could have missed something, of course. But usually it’s not this hard to find a specific study or case series or something
For example, here’s a pharmacy page: lithium is listed as lowering seizure threshold, but the reference is pretty generic.
Fortunately a 2003 summary by Lee et al is helpful. Bottom line: lithium at regular levels has no clear effect on seizures — some patients with epilepsy have improved, as well as a few who worsened. But when lithium gets too high (“lithium toxicity”) seizures are associated. Another reason not to let it get too high.
Here’s the section from Lee and colleagues on lithium: