Can traumatic brain injury cause of becoming bi-polor?

Sort of...: Head injury can injure the brain in such a way that the symptoms mimic bipolar disorder with impulsivity, irritability and mood instabilty. It wouldn't be true bipolar per the dsm but we would essentially treat it the same way with mood stabilizers and possibly antidepressants.

It happens: Undder our current nomenclature it would end up being classified as a mood disorder due to traumatic brain injury, rather than bipolar disorder. There is no litmus test, so a lot of it will depend on clinical history. Usually this is more common with significant right hemispher brain injuries. Some people will become acutely manic after a tbi and require sedation. Genetics may play a role.