Final answer:
The primary requirement for a diagnosis of bipolar I disorder is at least one manic episode. Depressive episodes are common in bipolar I, but not required for diagnosis. Manic episodes are defined by elevated mood and increased energy lasting at least one week.
Step-by-step explanation:
The primary requirement for a diagnosis of bipolar I disorder is a) At least 1 manic episode. Bipolar I disorder is characterized by one or more manic episodes or mixed episodes (which are periods of symptoms of both mania and depression). A manic episode is a distinct period of abnormally and persistently elevated, expansive, or irritable mood and abnormally and persistently increased activity or energy that lasts at least one week and is present for most of the day, nearly every day.
While depressive episodes are common in bipolar I disorder, they are not a requirement for the diagnosis. Other factors like a family history of bipolar disorder or a history of substance abuse can be relevant to the diagnosis but are not primary criteria. Proper diagnosis and treatment are crucial as mood disorders, including bipolar disorder, are among the most common causes of illness-related hospitalization in the U.S., and can significantly impact daily living and cognitive performance, particularly in educational settings.