The actual cause is unknown. However, there are some predisposing factors such as a family history of bipolar disorder, some drugs or medication may trigger manic episodes especially the Selective Serotonin Reuptake Inhibitors (SSRIs), substance abuse, personality disorders, anxiety disorders, etc.
There are a few different types of bipolar disorders, but there are some common features.
Bipolar I disorder
Bipolar II disorder
Cyclothymia