Mental illness refers to a wide range of conditions that affect a person's thinking, emotions, behavior, and overall mental well-being. These conditions can vary in severity and may include disorders such as depression, anxiety, schizophrenia, bipolar disorder, and eating disorders, among others. It is important to seek help from a mental health professional if you or someone you know is experiencing symptoms of a mental illness. Treatment options may include therapy, medication, and lifestyle changes to help manage symptoms and improve overall mental health.