Do your moods change from extremely happy, to very depressed over any given period of time? When depressed to you often think about suicide or hurting yourself or another? Do you feel the need to sleep more, and lack stamina or energy? This is called the depressive state of Bipolar Disorder.
Do you ever feel extremely powerful, have racing thoughts, and take on activities that you normally wouldn't? Do you have rare beliefs; for example that you have magical powers? You lack the need for sleep, and often don't eat for several days? This is called Manic Mania; a part of Bipolar Disorder.
Moods often change for everyone at a different pace, but there can also be psychotic episodes in between or during these moods. You may see or hear things that are not there. You may also believe false things; for example that everyone is out to get you. Paranoia is common with this disorder.
If you think that you or a loved one could be suffering from this disorder then seek out medical help immediately! Medication and therapy is usually involved, but treatment always depends on the particular patient.