1 DNA and proteins are key molecules of the cell nucleus. 2  One gene makes one protein. 3  A gene is made of DNA. 4  Bacteria and viruses have DNA too. 5  The DNA molecule is shaped like a twisted ladder. 6  A half DNA ladder is a template for copying the whole.  RNA is an intermediary between DNA and protein.
1 Another theory holds that depression may directly damage the brain, leading to dementia. âSimply put, chronic stress and/or depression may result in the release of cortisol,â Gorman says. Over time, this stress hormone can harm the brain, she says.  A third theory points to reduced brain volume.
Alzheimer's disease is the most common cause. Stroke is the second most common cause of dementia. Dementia caused by stroke is called vascular dementia. Some causes of dementia can be reversed with treatment, but most cannot. Causes that cannot be reversed. Common causes of dementia that cannot be reversed are: Parkinson's disease. Dementia is common in people with this condition. Dementia with Lewy bodies. It can cause short-term memory loss. Frontotemporal dementia, a group of diseases that includes Pick's disease. Severe head injury that caused a loss of consciousness.