. . . decision making, short-term memory loss, ability to focus on tasks, etc., many of which are the exact same symptoms of dementia and Alzheimer's but with different neurological causes), when the depression has gone far beyond just a simple mood disorder?

Dementia and depressions are two different disorders, and are diagnosed and treated differently. it important to visit a doctor, so you (or your loved one) can be diagnosed and treated properly.

Here is some information on both depression and dementia that might help you:

agingcare.com/Health-Conditio…

agingcare.com/Health-Conditio…

No is not correct.. because people who are depressed.. arent forgetful in itself. and have all neurological functions . some function better than others on different levels . and depending on the medications. the side effects of mind and cognative thinking is improved or not depending on the persons reaction to the medication.