Chronic depression interrupted by relatively short bouts of mania or hypomania are the key features of bipolar disorders, which are recurrent and debilitating conditions that can be difficult to treat and are frequently misdiagnosed. Bipolar disorder is one of the top three leading causes of disability in the United States along with chronic pain disorder and back problems. This chapter is devoted to the diagnosis and treatment of the following bipolar and related disorders: bipolar I, bipolar II, cyclothymic disorder, substance/medication-induced bipolar and related disorder, bipolar and related disorder due to another medical condition, other specified bipolar and related disorder, and unspecified bipolar and related disorder. All the bipolar disorders include a combination of mood episodes, depressive episodes, and a variety of symptom specifiers, all in different degrees and at different levels.