What is the primary reason for monitoring lithium levels every two to three days until a therapeutic level is obtained?

A. Postpartum depression occurs after childbirth and is usually treated with a combination of psychotherapy, antidepressant medication, and support. While light therapy might have some benefits for mood disorders, it is not the primary treatment for postpartum depression.
B. Seasonal affective disorder is a type of depression that typically occurs at certain times of the year, usually in the winter months when there is less natural sunlight. Phototherapy, or light therapy, is considered an effective treatment for SAD as it helps to mimic natural sunlight and improve mood by influencing circadian rhythms and serotonin levels.
C. While light therapy can have effects on mood, it is generally not used as a primary treatment for bipolar disorder. Bipolar disorder is often managed with mood stabilizers and other medications to prevent mood swings.
D. While light therapy can be beneficial for some types of depression, it is not typically the first-line treatment for moderate depression. Moderate depression is usually treated with antidepressants, psychotherapy, or a combination of both.

A. Lithium has a narrow therapeutic index, meaning the difference between a therapeutic dose and a toxic dose is small. Frequent monitoring allows for early detection of rising lithium levels, preventing toxicity.
B. While monitoring lithium levels is important for overall treatment, it's not primarily used to identify relapse.
C. Lithium primarily affects the kidneys, not the liver. Liver function tests are important for overall health monitoring but are not the primary reason for frequent lithium level checks.
D. While this is a goal, the primary reason for such frequent monitoring is to prevent toxicity, which can occur rapidly.