If you worked several overtime hours and experienced low moods, tiredness, and jumbled thoughts, you might be exhausted. But if those symptoms persist for months and don’t respond to self-help, you could have bipolar disorder. It’s a less prevalent illness than depression, but its symptoms are treatable. What is Bipolar Disorder? Bipolar disorder (BD) is a mental illness leading to swings in mood, energy, and whether you think clearly. BD sufferers experience high moods (mania)