Psychiatric symptoms are not always the sole indication of brain tumors. They may exhibit mood disorders, psychosis, memory issues, personality changes, anxiety, or anorexia. The tumor itself can also cause these problems by pressing on areas of the brain that control mental functions. Brain tumors are the most common cancer in children and adolescents. They account for about 20 percent of all childhood cancers and 3 percent of adult cancers. The most frequent type of brain tumor in adults is a glioma, which is a cancer that starts in the brain cells. Brain tumors are classified by type: astrocytomas, oligodendrogliomas, ependymomas, and others. There are different treatments for brain tumors, depending upon their type and location. Surgery is usually combined with radiation therapy and chemotherapy. Patients may require multiple treatments over time. Cognitive deficits are very common in patients with brain tumors. These can be present before any other symptoms appear and they often improve after successful treatment of the tumor. However, some patients may suffer from permanent damage due to the effects of the tumor or treatments used to remove it. Psychiatric symptoms are less common but can occur with some frequency. Depression is the most common psychiatric symptom. Other symptoms include anxiety, irritability, aggression, hallucinations, and delusions.