Delusion is a type of serious mental disorder known as psychosis. Psychosis is characterized by the disconnect between thought, imagination and emotions, with actual reality. People who experience delusions often have experiences that are far from reality. People with delusional disorders believe things that are not real or not according to the actual situation. Although it has been proven that what is believed by the patient is different from reality, the patient still holds fast to his thoughts. Causes and Types of Delusional Disorders The cause of delusional disorders is not known with certainty, but there are a variety of driving factors, including heredity or genetic, biological, environmental, and psychological. There is a tendency that delusional disorders can occur in people who have a family history of delusional disorders or schizophrenia. Several factors can trigger delusions, including stress, drug abuse, consuming excessive alcoholic drinks or abnormal brain functio