Dementia and Delirium are two somewhat broad biological phenomenon that are biological causes of mental illness. These interfere with biological processes with the brain. If we wish to be more specific, Cancers, Alzheimer and Parkinson's Disease can affect the brain by pressing on important aspects (Brain Cancer's) and/or cause progressive degeneration (Alzheimer and Parkinson's)
Most people who have high blood pressure do not have symptoms. In some cases, people with high blood pressure may have a pounding feeling in their head or chest, a feeling of lightheadedness or dizziness, or other signs.
