Schizophrenia is defined as an inability to differentiate between what is real and unreal – affecting decision-making, emotions, and behavior. A lot of research has gone into determining the causes of the disorder, but they are still unknown. However, a genetic component, possibly triggered by an environmental component, appears to be at play. Ultimately, the genetic component is likely several genes rather than a single gene. This is because the disorder can vary in severity and manifestation, with several subtypes recognized by the medical community. Read more about the genetics underlying schizophrenia.