Many medical and mental health researchers believe that lithium strengthens the connections between the mood-regulating nerve cells within the brain to stabilize the moods of individuals with major depressive disorders, according to WebMD. As of 2015, theories suggesting why lithium is so effective have not been proven.
Medications containing lithium help prevent manic symptoms in patients with such major depressive disorders as bipolar, claims WebMD. New users may not begin experiencing changes in symptoms until several weeks have passed. However, once the medication begins working, it may be used for prolonged periods of time to prevent future episodes of mania and depression from occurring. It may be taken alone or with other medications that treat depressive disorders.
Individuals taking lithium may need to see their physicians on a regular basis to ensure the medication remains at constant levels within their bodies, which enhances its effectiveness, says WebMD. They are advised to drink between eight and 12 glasses of water each day and to keep salt consumption to a minimum. Blood tests are taken at each visit to ensure the medication does not have a negative impact on kidney or thyroid function. Other side effects, such as increased thirst and urination, drowsiness and muscle weakness, are minor and may be eliminated by changing the individual's dose.