What causes psychosis is still unknown, but scientists and doctors have been working together to find some conclusive results for years. Through their studies, they have found some indications that psychosis is caused by what remain poorly understood combinations of biological factors that create sensitivity or vulnerability to psychotic symptoms during early teenage years to late teenage years. Since everybody is different, some factors may be greater in some people than in others. Since the cause is still so unclear, it is important that any individual experiencing symptoms get a thorough examination to help make the diagnosis as clear as possible.