Schizophrenia is a severe mental disorder that causes abnormalities in thinking, behavior, and emotion. It is caused by a combination of genetic, environmental, and neurological factors. Symptoms are categorized as positive (e.g. hallucinations, delusions) or negative (e.g. reduced speech, emotional expression) and can be triggered by stress, trauma, substance abuse, and family history. Treatment involves medication and therapy to help patients manage symptoms and rebuild their lives.