500
24 yr old office worker presented to the primary care physician with a one-month history of increasing fatigue, difficulty falling asleep, poor motivation and trouble paying attention especially in night school. There was no personal or family history of depression. Mirtazapine 15mg daily at bedtime was prescribed. After two doses, the patient suddenly became euphoric, hyperactive, talkative and full of creative ideas. The patient stood on a chair at night school and offered hearty congratulations to the teacher for contributing to the patient's certain future success. Which of the following diagnoses is best supported by the available evidence?
Substance induced bipolar disorder