Bipolar disorder is a brain disorder that causes shifts in mood between manic highs and depressive lows. It has genetic and biological causes and can begin in childhood. Symptoms include drastic changes in behavior and mood between manic and depressive states. In the classroom, teachers should not take mood changes personally, be attentive to students' feelings, watch for suicidal thoughts, help focus students on tasks, and engage them to create a supportive environment for students with bipolar disorder.