Is alzheimer's or dementia hereditary?

Yes to some degree: 60% of all pts with Alzheimer's Disease have first degree relative (often a parent) that had AD. There are genetic tests one called ApoE4 which can indicate you are low, medium or high risk in your life to develop this illness. I do not recommend such testing as there are no proven treatments that can slow or prevent Alzheimer's Disease from developing. Stay active mentally and physically!

Yes and no: If there is an illness that runs in your family you should speak to your doctor about it. There are many types of dementia. Some of them are genetically passed on while others aren't. The most common type of dementia is alzheimers disease and there are 2 forms. The early onset form is highly heritable. Alcoholic dementia is not inherited though a propensity for alcohol dependence can be.

Some are: For early onset Alzheimer's, there are 3 rare genes that increase risk markedly. These are very rare. For late onset, there in one main gene that elevates risk some (and 6 other genes under review). For frontotemporal dementias, genetics are behind about 40% of those cases.