There is no withdrawal syndrome with lithium. If lithium has been an effective drug for someone with bipolar disorder, however, stopping it increases the risk for a relapse. Beyond that, there is also this poorly understood phenomenon: After going off lithium, for about 10 to 15 percent of people who go back on it, the drug will no longer be effective.
Also, when stopping lithium, an abrupt discontinuation is not recommended. Instead, the drug is tapered down; this lessens the likelihood that the person will go into a mood episode. Should a mood episode develop while tapering down, it may also provide a person with needed information about the benefits of lithium in her particular situation.