Key Fact 1. Schizophrenia is a chronic and severe mental illness that affects around 20 million individuals worldwide, according to the World Health Organization. 2. Schizophrenia is defined by problems in thinking, perception, emotions, language, soul, and behavior, among other factors. Hallucinations (hearing voices or seeing things that are not there) and delusions are 2 … Continue reading Schizophrenia symptoms, causes, and treatment are all covered in this article!