Final answer:
The expected adverse effect of lithium that could lead to a bipolar disorder patient discontinuing their treatment is a fine hand tremor, which may interfere with daily activities.
Step-by-step explanation:
A nurse in a mental health clinic might encounter a client with bipolar disorder who has discontinued lithium treatment. Lithium is commonly used to manage bipolar disorder, and it's not uncommon for clients to stop taking it due to undesirable side effects. The nurse should be aware that one of the expected adverse effects (AE) of lithium that could lead to a patient stopping the medication is a fine hand tremor.
This is typically a minor but bothersome tremor of the hands that can interfere with daily activities and may become a reason for patients to become non-compliant with their treatment regimen.