Schizophrenia is a chronic, severe, and disabling disorder that causes people to experience hallucinations and delusions. While anyone can carry genes for schizophrenia, only some people will actually develop the full disorder. Research suggests that most people carrying schizophrenia genes are well family members who never show symptoms, and it takes a critical combination of multiple genes to cause the disease. Symptoms are categorized as positive, negative, or cognitive, and include problems with thought, movement, pleasure, attention, and memory. The causes are not fully understood but appear related to both genetic and environmental factors. Treatment involves antipsychotic medication and supportive therapies to help people better function in their daily lives.