There is no known way to prevent bipolar disorder.
Without treatment, people with bipolar disorder generally have lifelong episodes of mania and depression. The episodes tend to become more frequent and more severe. The disorder can disrupt social relationships and ability to work. The person may be unable to carry out normal daily activities. People with untreated bipolar disorder have a high risk for suicide.
Bipolar disorder is not contagious. However, it does tend to run in families.